refactor: improve notification naming and introduce type-safe enums

- Rename billFwd* to billsNotification* for clarity
- Rename rentDueNotification* to rentNotification* for consistency
- Rename utilBillsProofOfPayment to billsProofOfPayment
- Introduce enums for type safety:
  - BillsNotificationStrategy (WhenPayed, WhenAttached)
  - BillsNotificationStatus (Scheduled, Sent, Failed)
  - RentNotificationStatus (Sent, Failed)
- Replace "pending" status with "scheduled" for better semantics
- Fix function names to proper camelCase
- Fix incorrect import path in web-app/app/lib/format.ts

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

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

shared-code/src/db-types.ts

@@ -49,6 +49,29 @@ export enum EmailStatus {
     Unsubscribed = "unsubscribed"
 }
 
+export enum BillsNotificationStrategy {
+    /** Notify tenant when bill is payed */
+    WhenPayed = "when-payed",
+    /** Notify tenant when bill gets an attachment */
+    WhenAttached = "when-attached"
+}
+
+export enum BillsNotificationStatus {
+    /** Bills notification is scheduled to be sent */
+    Scheduled = "scheduled",
+    /** Bills notification has been sent */
+    Sent = "sent",
+    /** Sending of bills notification failed */
+    Failed = "failed"
+}
+
+export enum RentNotificationStatus {
+    /** notification has been sent */
+    Sent = "sent",
+    /** Sending of notification failed */
+    Failed = "failed"
+}
+
 /** bill object in the form returned by MongoDB */
 export interface BillingLocation {
     _id: string;
@@ -84,25 +107,25 @@ export interface BillingLocation {
     /** (optional) language for tenant notification emails */
     tenantEmailLanguage?: "hr" | "en" | null;
     /** (optional) whether to automatically notify tenant */
-    billFwdEnabled?: boolean | null;
+    billsNotificationEnabled?: boolean | null;
     /** (optional) bill forwarding strategy */
-    billFwdStrategy?: "when-payed" | "when-attached" | null;
+    billsNotificationStrategy?: BillsNotificationStrategy | null;
     /** (optional) bill forwarding status */
-    billFwdStatus?: "pending" | "sent" | "failed" | null;
+    billsNotificationStatus?: BillsNotificationStatus | null;
+    /** (optional) utility bills proof of payment attachment */
+    billsProofOfPayment?: FileAttachment|null;
     /** (optional) whether to automatically send rent notification */
-    rentDueNotificationEnabled?: boolean | null;
+    rentNotificationEnabled?: boolean | null;
+    /** (optional) when was the rent due notification sent */
+    rentNotificationStatus?: RentNotificationStatus | null;
+    /** (optional) rent proof of payment attachment */
+    rentProofOfPayment?: FileAttachment|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 */