Remove unused backend infrastructure and template files for Gallus CMS.

- Deleted `backend/.env.local`, admin page, and OAuth callback page.
- Removed legacy Docker configurations [`docker-compose.yml`, `Dockerfile.caddy`].
- Deprecated migration script, unused routes, and event/gallery migration documentation.
- Updated gitignore to reflect removed folder structure.

backend/Dockerfile

@@ -10,8 +10,7 @@ RUN apk add --no-cache python3 make g++
 
 # Install dependencies
 COPY package*.json ./
-# Use npm ci when lockfile exists, fallback to npm install for local/dev
-RUN npm ci || npm install
+RUN npm ci
 
 # Copy source
 COPY . .
@@ -27,8 +26,17 @@ WORKDIR /app
 # Install runtime dependencies (git for simple-git, sqlite3 CLI tool)
 RUN apk add --no-cache git sqlite
 
-# Copy production dependencies from builder (already compiled native modules)
-COPY --from=builder /app/node_modules ./node_modules
+# Install build dependencies for better-sqlite3 (needed for npm ci)
+RUN apk add --no-cache python3 make g++
+
+# Copy package files
+COPY package*.json ./
+
+# Install production dependencies only
+RUN npm ci --production
+
+# Remove build dependencies after install
+RUN apk del python3 make g++
 
 # Copy built files from builder
 COPY --from=builder /app/dist ./dist
@@ -55,5 +63,5 @@ ENV DATABASE_PATH=/app/data/gallus_cms.db
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
   CMD node -e "require('http').get('http://localhost:8080/health', (r) => {process.exit(r.statusCode === 200 ? 0 : 1)})"
 
-# Run DB migrations if present, then start application
-CMD ["/bin/sh", "-lc", "[ -f dist/migrate.js ] && node dist/migrate.js || true; node dist/index.js"]
+# Start application
+CMD ["node", "dist/index.js"]