Fix: Revert to inline shared types (Turbopack can't resolve path aliases)

Turbopack doesn't support tsconfig path aliases pointing outside
the project root. Reverted to copying shared types directly into
each service. The canonical source remains shared/types/*.ts,
synced via scripts/sync-shared-types.sh.

Changes:
- Reverted docker-compose.yml contexts to ./service
- Reverted Dockerfiles to simple COPY . .
- Removed @shared/* from tsconfigs
- Removed symlinks + .gitignore hacks
- Added scripts/sync-shared-types.sh for keeping copies in sync

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

website/Dockerfile

@@ -4,14 +4,13 @@ FROM node:20-alpine AS builder
 WORKDIR /app
 
 # Copy package files
-COPY website/package.json website/package-lock.json* ./
+COPY package.json package-lock.json* ./
 
 # Install dependencies
 RUN npm install
 
-# Copy source code + shared types (inside project for Turbopack)
-COPY website/ .
-COPY shared/ ./shared/
+# Copy source code
+COPY . .
 
 # Build arguments for environment variables
 ARG NEXT_PUBLIC_BILLING_API_URL