refactor: move Docker build files to web-app directory

Moved Dockerfile, build.sh, and .dockerignore to web-app/ for better
project encapsulation. Each project now contains its own build configuration.

## Changes
- Moved Dockerfile to web-app/ and simplified paths
- Moved build.sh to web-app/
- Moved .dockerignore to web-app/
- Updated Dockerfile to work from web-app/ context (no workspace references)
- Updated documentation for new build workflow

## Build Workflow
- Build: Run from web-app/ directory (`cd web-app && ./build.sh 2.20.0`)
- Deploy: Run from repository root (`./deploy-standalone.sh 2.20.0`)

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

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

CLAUDE.md

@@ -30,9 +30,12 @@ All commands should be run from within the respective project directory.
 
 ## Deployment Commands
 
-- `./build.sh` - Build Docker image for deployment
-- `./deploy.sh` - Deploy Docker service to production
-- `./debug-deploy.sh` - Deploy with debug configuration
+**Building Docker Image** (from web-app directory):
+- `cd web-app && ./build.sh <version>` - Build Docker image
+
+**Deploying** (from repository root):
+- `./deploy-standalone.sh <version>` - Deploy with docker-compose (standalone)
+- `./deploy-swarm.sh <version>` - Deploy with Docker Swarm
 
 ## Architecture Overview