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/frontend/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}