Clean up repository hygiene

- Expand .gitignore with editor state, secrets, logs, and archive patterns
- Remove AdminCategoriesViewV2.vue (replaced, no remaining references)
- Exclude accidental AdminContentView duplicate from tsconfig

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

frontend/tsconfig.app.json

@@ -10,5 +10,6 @@
     "erasableSyntaxOnly": true,
     "noFallthroughCasesInSwitch": true
   },
-  "include": ["src/**/*.ts", "src/**/*.tsx", "src/**/*.vue"]
+  "include": ["src/**/*.ts", "src/**/*.tsx", "src/**/*.vue"],
+  "exclude": ["src/views/admin/AdminContentView 2.vue"]
 }