Migrate Angular 2 to Angular 19 with standalone components

- Upgrade Angular, Firebase, and AngularFire to latest versions
- Replace NgModules with standalone components and bootstrapApplication
- Replace angular-cli.json with angular.json and ESLint
- Add Firebase App Check with reCAPTCHA v3 for abuse protection
- Move Firebase config out of version control (firebaseConfig.example.ts)
- Fix AngularFire injection context errors using runInInjectionContext
- Implement drag-and-drop reordering within and across columns
- Add inline editing for card title and description
- Add subtask deletion with confirmation modal
- Refresh UI with modern card-based look and feel

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

tsconfig.json

@@ -0,0 +1,27 @@
+/* To learn more about Typescript configuration file: https://www.typescriptlang.org/docs/handbook/tsconfig-json.html. */
+/* To learn more about Angular compiler options: https://angular.dev/reference/configs/angular-compiler-options. */
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "outDir": "./dist/out-tsc",
+    "strict": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "skipLibCheck": true,
+    "isolatedModules": true,
+    "esModuleInterop": true,
+    "experimentalDecorators": true,
+    "moduleResolution": "bundler",
+    "importHelpers": true,
+    "target": "ES2022",
+    "module": "ES2022"
+  },
+  "angularCompilerOptions": {
+    "enableI18nLegacyMessageIdFormat": false,
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  }
+}