fix: add missing tsconfig files and restore npm run build

tsconfig.json, tsconfig.app.json, and tsconfig.node.json were never
committed because *.json was gitignored without exceptions for them.
Added whitelist entries and restored Dockerfile to use npm run build
(tsc -b + vite) now that the config files are present.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

flight-comparator/Dockerfile.frontend

@@ -5,7 +5,7 @@ WORKDIR /app
 COPY frontend/package*.json ./
 RUN npm ci
 COPY frontend/ .
-RUN npx vite build
+RUN npm run build
 
 # ── Stage 2: Serve with nginx ──────────────────────────────────────────────
 FROM nginx:alpine