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>

.editorconfig

@@ -1,4 +1,4 @@
-# Editor configuration, see http://editorconfig.org
+# Editor configuration, see https://editorconfig.org
 root = true
 
 [*]
@@ -8,6 +8,10 @@ indent_size = 2
 insert_final_newline = true
 trim_trailing_whitespace = true
 
+[*.ts]
+quote_type = single
+ij_typescript_use_double_quotes = false
+
 [*.md]
 max_line_length = off
 trim_trailing_whitespace = false