refactor: migrate web-app to use shared-code package

Update web-app to use @evidencija-rezija/shared-code for common types
and utilities instead of maintaining duplicate copies.

Changes:
- Add shared-code dependency to package.json
- Update all imports across 35+ files to use @evidencija-rezija/shared-code
- Remove duplicate db-types.ts and shareChecksum.ts files

This ensures type consistency between web-app and email-worker and
reduces maintenance burden.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

web-app/app/[locale]/email/unsubscribe/[id]/page.tsx

@@ -2,8 +2,8 @@ import { Suspense } from 'react';
 import EmailUnsubscribePage from './EmailUnsubscribePage';
 import { Main } from '@/app/ui/Main';
 import { getDbClient } from '@/app/lib/dbClient';
-import { BillingLocation, EmailStatus } from '@/app/lib/db-types';
+import { BillingLocation, EmailStatus } from '@evidencija-rezija/shared-code';
-import { extractShareId, validateShareChecksum } from '@/app/lib/shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 import { notFound } from 'next/navigation';
 
 export default async function Page({ params: { id } }: { params: { id: string } }) {

web-app/app/[locale]/email/verify/[id]/page.tsx

@@ -2,8 +2,8 @@ import { Suspense } from 'react';
 import EmailVerifyPage from './EmailVerifyPage';
 import { Main } from '@/app/ui/Main';
 import { getDbClient } from '@/app/lib/dbClient';
-import { BillingLocation, EmailStatus } from '@/app/lib/db-types';
+import { BillingLocation, EmailStatus } from '@evidencija-rezija/shared-code';
-import { extractShareId, validateShareChecksum } from '@/app/lib/shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 import { notFound } from 'next/navigation';
 
 export default async function Page({ params: { id } }: { params: { id: string } }) {

web-app/app/[locale]/home/location/[id]/add/LocationAddPage.tsx

@@ -1,5 +1,5 @@
 import { LocationEditForm } from '@/app/ui/LocationEditForm';
-import { YearMonth } from '@/app/lib/db-types';
+import { YearMonth } from '@evidencija-rezija/shared-code';
 import { getUserSettings } from '@/app/lib/actions/userSettingsActions';
 
 export default async function LocationAddPage({ yearMonth }: { yearMonth:YearMonth }) {

web-app/app/[locale]/home/multi-bill-edit/[year]/[month]/BillToggleBadge.tsx

@@ -1,5 +1,5 @@
 import { FC } from "react"
-import { Bill } from "@/app/lib/db-types"
+import { Bill } from "@evidencija-rezija/shared-code"
 import { TicketIcon } from "@heroicons/react/24/outline"
 
 export interface BillBadgeProps {

web-app/app/[locale]/home/multi-bill-edit/[year]/[month]/MultiBillEdit.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { FC, useState } from "react";
-import { BillingLocation, YearMonth } from "../../../../../lib/db-types";
+import { BillingLocation, YearMonth } from "@evidencija-rezija/shared-code";
 import { formatYearMonth } from "../../../../../lib/format";
 import { useTranslations } from "next-intl";
 import { useRouter } from "next/navigation";

web-app/app/[locale]/home/multi-bill-edit/[year]/[month]/MultiBillEditButton.tsx

@@ -2,7 +2,7 @@
 
 import { InboxStackIcon, Square3Stack3DIcon } from '@heroicons/react/24/outline';
 import { useTranslations } from 'next-intl';
-import { YearMonth } from '../../../../../lib/db-types';
+import { YearMonth } from '@evidencija-rezija/shared-code';
 import Link from 'next/link';
 
 export interface MultiBillEditButtonProps {

web-app/app/[locale]/share/attachment/[id]/route.tsx

@@ -1,8 +1,8 @@
 import { fetchBillById } from '@/app/lib/actions/billActions';
 import { notFound } from 'next/navigation';
-import { extractShareId, validateShareChecksum } from '@/app/lib/shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 import { getDbClient } from '@/app/lib/dbClient';
-import { BillingLocation } from '@/app/lib/db-types';
+import { BillingLocation } from '@evidencija-rezija/shared-code';
 
 export async function GET(request: Request, { params: { id } }: { params: { id: string } }) {
     // Parse shareId-billID format

web-app/app/[locale]/share/proof-of-payment/combined/[id]/route.tsx

@@ -1,7 +1,7 @@
 import { getDbClient } from '@/app/lib/dbClient';
-import { BillingLocation } from '@/app/lib/db-types';
+import { BillingLocation } from '@evidencija-rezija/shared-code';
 import { notFound } from 'next/navigation';
-import { extractShareId, validateShareChecksum } from '@/app/lib/shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 
 export async function GET(request: Request, { params: { id } }: { params: { id: string } }) {
     const shareId = id;

web-app/app/[locale]/share/proof-of-payment/per-bill/[id]/route.tsx

@@ -1,7 +1,7 @@
 import { getDbClient } from '@/app/lib/dbClient';
-import { BillingLocation } from '@/app/lib/db-types';
+import { BillingLocation } from '@evidencija-rezija/shared-code';
 import { notFound } from 'next/navigation';
-import { extractShareId, validateShareChecksum } from '@/app/lib/shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 
 export async function GET(_request: Request, { params: { id } }: { params: { id: string } }) {
     // Parse shareId-billID format

web-app/app/lib/actions/billActions.ts

@@ -10,7 +10,7 @@ import { gotoHomeWithMessage } from './navigationActions';
 import { getTranslations, getLocale } from "next-intl/server";
 import { IntlTemplateFn } from '@/app/i18n';
 import { unstable_noStore, revalidatePath } from 'next/cache';
-import { extractShareId, validateShareChecksum } from '../shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 import { validatePdfFile } from '../validators/pdfValidator';
 import { checkUploadRateLimit } from '../uploadRateLimiter';
 

web-app/app/lib/actions/emailActions.ts

@@ -2,7 +2,7 @@
 
 import { getDbClient } from '../dbClient';
 import { BillingLocation, EmailStatus } from '../db-types';
-import { extractShareId, validateShareChecksum } from '../shareChecksum';
+import { extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 import { revalidatePath } from 'next/cache';
 
 export type EmailActionResult = {

web-app/app/lib/actions/locationActions.ts

@@ -10,7 +10,7 @@ import { gotoHomeWithMessage } from './navigationActions';
 import { unstable_noStore, revalidatePath } from 'next/cache';
 import { IntlTemplateFn } from '@/app/i18n';
 import { getTranslations, getLocale } from "next-intl/server";
-import { generateShareId, extractShareId, validateShareChecksum } from '../shareChecksum';
+import { generateShareId, extractShareId, validateShareChecksum } from '@evidencija-rezija/shared-code';
 import { validatePdfFile } from '../validators/pdfValidator';
 import { checkUploadRateLimit } from '../uploadRateLimiter';
 

web-app/app/lib/db-types.ts

@@ -1,144 +0,0 @@
-import { unsubscribe } from "diagnostics_channel";
-
-export interface FileAttachment {
-    fileName: string;
-    fileSize: number;
-    fileType: string;
-    fileLastModified: number;
-    fileContentsBase64: string;
-    uploadedAt: Date;
-};
-
-export interface YearMonth {
-    year: number;
-    month: number;
-};
-
-/** User settings data */
-export interface UserSettings {
-    /** user's ID */
-    userId: string;
-    /** whether enableshow IBAN payment instructions in monthly statement */
-    enableIbanPayment?: boolean | null;
-    /** owner name */
-    ownerName?: string | null;
-    /** owner street */
-    ownerStreet?: string | null;
-    /** owner town */
-    ownerTown?: string | null;
-    /** owner IBAN */
-    ownerIBAN?: string | null;
-    /** currency (ISO 4217) */
-    currency?: string | null;
-    /** whether to enable Revolut payment instructions in monthly statement */
-    enableRevolutPayment?: boolean | null;
-    /** owner Revolut payment link */
-    ownerRevolutProfileName?: string | null;
-};
-
-export enum EmailStatus {
-    /** Email is not yet verified - recipient has not yet confirmed their email address */
-    Unverified = "unverified",
-    /** Email is not yet verified - a verification request has been sent */
-    VerificationPending = "verification-pending",
-    /** sending of verification email failed */
-    VerificationFailed = "verification-failed",
-    /** Email is verified and is in good standing: emails are being successfully delivered */
-    Verified = "verified",
-    /** Recepient has unsubscribed from receiving emails via link - no further emails will be sent */
-    Unsubscribed = "unsubscribed"
-}
-
-/** bill object in the form returned by MongoDB */
-export interface BillingLocation {
-    _id: string;
-    /** user's ID */
-    userId: string;
-    /** user's email */
-    userEmail?: string | null;
-    /** name of the location */
-    name: string;
-    /** billing period year and month */
-    yearMonth: YearMonth;
-    /** array of bills */
-    bills: Bill[];
-    /** (optional) notes */
-    notes: string|null;
-
-    /** (optional) method for showing payment instructions to tenant */
-    tenantPaymentMethod?: "none" | "iban" | "revolut" | null;
-
-    /** (optional) type of proof of payment attachment */
-    proofOfPaymentType: "none" | "combined" | "per-bill";
-
-    /** (optional) tenant name */
-    tenantName?: string | null;
-    /** (optional) tenant street */
-    tenantStreet?: string | null;
-    /** (optional) tenant town */
-    tenantTown?: string | null;
-    /** (optional) tenant email */
-    tenantEmail?: string | null;
-    /** (optional) tenant email status */
-    tenantEmailStatus?: EmailStatus | null;
-    /** (optional) whether to automatically notify tenant */
-    billFwdEnabled?: boolean | null;
-    /** (optional) bill forwarding strategy */
-    billFwdStrategy?: "when-payed" | "when-attached" | null;
-    /** (optional) bill forwarding status */
-    billFwdStatus?: "pending" | "sent" | "failed" | null;
-    /** (optional) whether to automatically send rent notification */
-    rentDueNotificationEnabled?: boolean | null;
-    /** (optional) day of month when rent is due (1-31) */
-    rentDueDay?: number | null;
-    /** (optional) when was the rent due notification sent */
-    rentDueNotificationStatus?: "sent" | "failed" | null;
-    /** (optional) monthly rent amount in cents */
-    rentAmount?: number | null;
-    /** (optional) whether the location has been seen by tenant */
-    seenByTenantAt?: Date | null;
-    /** (optional) utility bills proof of payment attachment */
-    utilBillsProofOfPayment?: FileAttachment|null;
-    /** (optional) rent proof of payment attachment */
-    rentProofOfPayment?: FileAttachment|null;
-    /** (optional) share link expiry timestamp */
-    shareTTL?: Date;
-    /** (optional) when tenant first visited the share link */
-    shareFirstVisitedAt?: Date | null;
-};
-
-export enum BilledTo {
-    Tenant = "tenant",
-    Landlord = "landlord"
-}
-
-/** Bill basic data */
-export interface Bill {
-    _id: string;
-    /** bill name */
-    name: string;
-    /** is the bill paid */
-    paid: boolean;
-    /** who is billed for the bill */
-    billedTo?: BilledTo;
-    /** payed amount amount in cents */
-    payedAmount?: number | null;
-    /** attached document (optional) */
-    attachment?: FileAttachment|null;
-    /**
-     * true if there an attachment
-     * @description this field enables us to send this info to the client without sending large attachment - it's an optimization
-    */
-    hasAttachment?: boolean;
-    /** (optional) notes */
-    notes?: string|null;
-    /** 
-     * (optional) image data containing PDF471 bar code
-     * @deprecated LEGACY FIELD - use hub3aText instead
-     * */
-    barcodeImage?:string;
-    /** (optional) HUB-3A text for generating PDF417 bar code */
-    hub3aText?:string;
-    /** (optional) proof of payment attachment */
-    proofOfPayment?: FileAttachment|null;
-};

web-app/app/lib/shareChecksum.ts

@@ -1,86 +0,0 @@
-import crypto from 'crypto';
-
-/**
- * Checksum length in hex characters (16 chars = 64 bits of entropy)
- */
-export const CHECKSUM_LENGTH = 16;
-
-/**
- * Generate share link checksum for location
- * Uses HMAC-SHA256 for cryptographic integrity
- *
- * SECURITY: Prevents location ID enumeration while allowing stateless validation
- */
-export function generateShareChecksum(locationId: string): string {
-  const secret = process.env.SHARE_LINK_SECRET;
-
-  if (!secret) {
-    throw new Error('SHARE_LINK_SECRET environment variable not configured');
-  }
-
-  return crypto
-    .createHmac('sha256', secret)
-    .update(locationId)
-    .digest('hex')
-    .substring(0, CHECKSUM_LENGTH);
-}
-
-/**
- * Validate share link checksum
- * Uses constant-time comparison to prevent timing attacks
- *
- * @param locationId - The location ID from URL
- * @param providedChecksum - The checksum from URL
- * @returns true if checksum is valid
- */
-export function validateShareChecksum(
-  locationId: string,
-  providedChecksum: string
-): boolean {
-  try {
-    const expectedChecksum = generateShareChecksum(locationId);
-
-    // Convert to buffers for timing-safe comparison
-    const expected = Buffer.from(expectedChecksum);
-    const provided = Buffer.from(providedChecksum);
-
-    // Length check (prevents timing attack on different lengths)
-    if (expected.length !== provided.length) {
-      return false;
-    }
-
-    // Constant-time comparison (prevents timing attacks)
-    return crypto.timingSafeEqual(expected, provided);
-  } catch {
-    return false;
-  }
-}
-
-/**
- * Generate combined location ID with checksum appended
- * @param locationId - The MongoDB location ID (24 chars)
- * @returns Combined ID: locationId + checksum (40 chars total)
- */
-export function generateShareId(locationId: string): string {
-  const checksum = generateShareChecksum(locationId);
-  return locationId + checksum;
-}
-
-/**
- * Extract location ID and checksum from combined share ID
- * @param shareId - Combined ID (locationId + checksum)
- * @returns Object with locationId and checksum, or null if invalid format
- */
-export function extractShareId(shareId: string): { locationId: string; checksum: string } | null {
-  // MongoDB ObjectID is 24 chars, checksum is 16 chars = 40 total
-  const expectedLength = 24 + CHECKSUM_LENGTH;
-
-  if (shareId.length !== expectedLength) {
-    return null;
-  }
-
-  const locationId = shareId.substring(0, 24);
-  const checksum = shareId.substring(24);
-
-  return { locationId, checksum };
-}

web-app/app/ui/AddLocationButton.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { PlusCircleIcon, HomeIcon } from "@heroicons/react/24/outline";
-import { YearMonth } from "../lib/db-types";
+import { YearMonth } from '@evidencija-rezija/shared-code';
 import { formatYearMonth } from "../lib/format";
 import Link from "next/link";
 import { useTranslations } from 'next-intl';

web-app/app/ui/AddMonthButton.tsx

@@ -3,7 +3,7 @@
 import { PlusCircleIcon, CalendarDaysIcon } from "@heroicons/react/24/outline";
 import React from "react";
 import { formatYearMonth } from "../lib/format";
-import { YearMonth } from "../lib/db-types";
+import { YearMonth } from '@evidencija-rezija/shared-code';
 import Link from "next/link";
 import { useLocale, useTranslations } from 'next-intl';
 

web-app/app/ui/BillBadge.tsx

@@ -1,5 +1,5 @@
 import { FC } from "react"
-import { Bill } from "@/app/lib/db-types"
+import { Bill } from "@evidencija-rezija/shared-code"
 import Link from "next/link"
 import { TicketIcon } from "@heroicons/react/24/outline"
 

web-app/app/ui/BillDeleteForm.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { FC, ReactNode, useState } from "react";
-import { Bill, BillingLocation } from "../lib/db-types";
+import { Bill, BillingLocation } from '@evidencija-rezija/shared-code';
 import { useFormState } from "react-dom";
 import { Main } from "./Main";
 import { deleteBillById } from "../lib/actions/billActions";

web-app/app/ui/BillEditForm.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { DocumentIcon, TicketIcon, TrashIcon } from "@heroicons/react/24/outline";
-import { Bill, BilledTo, BillingLocation } from "../lib/db-types";
+import { Bill, BilledTo, BillingLocation } from '@evidencija-rezija/shared-code';
 import React, { FC, useEffect } from "react";
 import { useFormState } from "react-dom";
 import { updateOrAddBill } from "../lib/actions/billActions";

web-app/app/ui/HomePage.tsx

@@ -1,7 +1,7 @@
 import { fetchAllLocations } from '@/app/lib/actions/locationActions';
 import { fetchAvailableYears } from '@/app/lib/actions/monthActions';
 import { getUserSettings } from '@/app/lib/actions/userSettingsActions';
-import { BillingLocation, YearMonth } from '@/app/lib/db-types';
+import { BillingLocation, YearMonth } from '@evidencija-rezija/shared-code';
 import { FC } from 'react';
 import { MonthLocationList } from '@/app/ui/MonthLocationList';
 

web-app/app/ui/LocationCard.tsx

@@ -3,7 +3,7 @@
 import { CheckCircleIcon, Cog8ToothIcon, PlusCircleIcon, ShareIcon, BanknotesIcon, EyeIcon, TicketIcon, ShoppingCartIcon, EnvelopeIcon, ExclamationTriangleIcon, ClockIcon, XCircleIcon } from "@heroicons/react/24/outline";
 import { FC } from "react";
 import { BillBadge } from "./BillBadge";
-import { BillingLocation, EmailStatus } from "../lib/db-types";
+import { BillingLocation, EmailStatus } from '@evidencija-rezija/shared-code';
 import { formatYearMonth } from "../lib/format";
 import { formatCurrency } from "../lib/formatStrings";
 import Link from "next/link";

web-app/app/ui/LocationDeleteForm.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { FC, ReactNode, useState } from "react";
-import { BillingLocation } from "../lib/db-types";
+import { BillingLocation } from '@evidencija-rezija/shared-code';
 import { deleteLocationById } from "../lib/actions/locationActions";
 import { useFormState } from "react-dom";
 import Link from "next/link";

web-app/app/ui/LocationEditForm.tsx

@@ -2,7 +2,7 @@
 
 import { TrashIcon, ExclamationTriangleIcon, ClockIcon, EnvelopeIcon, CheckCircleIcon, PencilSquareIcon, XCircleIcon } from "@heroicons/react/24/outline";
 import { FC, useState } from "react";
-import { BillingLocation, UserSettings, YearMonth, EmailStatus } from "../lib/db-types";
+import { BillingLocation, UserSettings, YearMonth, EmailStatus } from '@evidencija-rezija/shared-code';
 import { updateOrAddLocation } from "../lib/actions/locationActions";
 import { useFormState } from "react-dom";
 import Link from "next/link";

web-app/app/ui/MonthCard.tsx

@@ -2,7 +2,7 @@
 
 import { FC, useEffect, useRef } from "react";
 import { formatYearMonth } from "../lib/format";
-import { YearMonth } from "../lib/db-types";
+import { YearMonth } from '@evidencija-rezija/shared-code';
 import { formatCurrency } from "../lib/formatStrings";
 import { useTranslations } from "next-intl";
 

web-app/app/ui/MonthLocationList.tsx

@@ -7,7 +7,7 @@ import { MonthCard } from "./MonthCard";
 import Pagination from "./Pagination";
 import { LocationCard } from "./LocationCard";
 import { PrintButton } from "./PrintButton";
-import { BillingLocation, UserSettings, YearMonth } from "../lib/db-types";
+import { BillingLocation, UserSettings, YearMonth } from '@evidencija-rezija/shared-code';
 import { useRouter, useSearchParams } from "next/navigation";
 import { ToastContainer, toast } from 'react-toastify';
 import 'react-toastify/dist/ReactToastify.css';

web-app/app/ui/PrintButton.tsx

@@ -2,7 +2,7 @@
 
 import { PrinterIcon } from '@heroicons/react/24/outline';
 import { useTranslations } from 'next-intl';
-import { YearMonth } from '../lib/db-types';
+import { YearMonth } from '@evidencija-rezija/shared-code';
 
 export interface PrintButtonProps {
   yearMonth: YearMonth;

web-app/app/ui/UserSettingsForm.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { FC, useState } from "react";
-import { UserSettings } from "../lib/db-types";
+import { UserSettings } from '@evidencija-rezija/shared-code';
 import { updateUserSettings } from "../lib/actions/userSettingsActions";
 import { useFormState, useFormStatus } from "react-dom";
 import { useLocale, useTranslations } from "next-intl";

web-app/app/ui/ViewBillBadge.tsx

@@ -1,5 +1,5 @@
 import { FC } from "react";
-import { Bill } from "@/app/lib/db-types";
+import { Bill } from "@evidencija-rezija/shared-code";
 import Link from "next/link";
 import { TicketIcon } from "@heroicons/react/24/outline";
 import { useLocale } from "next-intl";

web-app/app/ui/ViewBillCard.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { TicketIcon, CheckCircleIcon, XCircleIcon, DocumentIcon } from "@heroicons/react/24/outline";
-import { Bill, BillingLocation } from "../lib/db-types";
+import { Bill, BillingLocation } from '@evidencija-rezija/shared-code';
 import { FC, useState } from "react";
 import Link from "next/link";
 import { useRouter } from "next/navigation";

web-app/app/ui/ViewLocationCard.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { FC, useMemo, useState } from "react";
-import { BilledTo, BillingLocation, UserSettings } from "../lib/db-types";
+import { BilledTo, BillingLocation, UserSettings } from '@evidencija-rezija/shared-code';
 import { formatYearMonth } from "../lib/format";
 import { formatCurrency, formatIban } from "../lib/formatStrings";
 import { useTranslations } from "next-intl";

web-app/package.json

@@ -9,6 +9,7 @@
     "seed": "node -r dotenv/config ./scripts/seed.js"
   },
   "dependencies": {
+    "@evidencija-rezija/shared-code": "^1.0.0",
     "@emotion/react": "^11.14.0",
     "@emotion/styled": "^11.14.1",
     "@heroicons/react": "^2.0.18",