Align repo config with global development standards

- Add missing tsconfig strictness flags (noUncheckedIndexedAccess,
  exactOptionalPropertyTypes, noImplicitOverride,
  noPropertyAccessFromIndexSignature) and fix all resulting type errors
- Replace ESLint/Prettier with oxlint 1.48.0 and oxfmt 0.33.0
- Pin all frontend and backend dependencies to exact versions
- Pin GitHub Actions to SHA hashes with persist-credentials: false
- Fix CI Python version mismatch (3.12 -> 3.14) and ruff target-version
- Add vitest 4.0.18 with jsdom environment for frontend testing
- Add ty 0.0.17 for Python type checking (non-blocking in CI)
- Add actionlint and zizmor CI job for workflow linting and security audit
- Add Dependabot config for npm, pip, and github-actions
- Update CLAUDE.md and pre-commit hooks to reflect new tooling
- Ignore Claude Code sandbox artifacts in gitignore

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

frontend/package.json

@@ -6,35 +6,34 @@
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
-    "lint": "eslint .",
-    "preview": "vite preview"
+    "lint": "oxlint src/",
+    "format": "oxfmt --write src/",
+    "format:check": "oxfmt --check src/",
+    "preview": "vite preview",
+    "test": "vitest run",
+    "test:watch": "vitest"
   },
   "dependencies": {
-    "@dnd-kit/core": "^6.3.1",
-    "@dnd-kit/sortable": "^10.0.0",
-    "@dnd-kit/utilities": "^3.2.2",
-    "@tanstack/react-query": "^5.90.20",
-    "react": "^19.2.0",
-    "react-dom": "^19.2.0",
-    "react-router-dom": "^7.13.0",
-    "sonner": "^2.0.7"
+    "@dnd-kit/core": "6.3.1",
+    "@dnd-kit/sortable": "10.0.0",
+    "@dnd-kit/utilities": "3.2.2",
+    "@tanstack/react-query": "5.90.20",
+    "react": "19.2.4",
+    "react-dom": "19.2.4",
+    "react-router-dom": "7.13.0",
+    "sonner": "2.0.7"
   },
   "devDependencies": {
-    "@eslint/js": "^9.39.1",
-    "@tailwindcss/vite": "^4.1.18",
-    "@types/node": "^24.10.1",
-    "@types/react": "^19.2.5",
-    "@types/react-dom": "^19.2.3",
-    "@vitejs/plugin-react": "^5.1.1",
-    "eslint": "^9.39.1",
-    "eslint-config-prettier": "^10.1.8",
-    "eslint-plugin-react-hooks": "^7.0.1",
-    "eslint-plugin-react-refresh": "^0.4.24",
-    "globals": "^16.5.0",
-    "prettier": "^3.8.1",
-    "tailwindcss": "^4.1.18",
-    "typescript": "~5.9.3",
-    "typescript-eslint": "^8.46.4",
-    "vite": "^7.2.4"
+    "@tailwindcss/vite": "4.1.18",
+    "@types/node": "24.10.10",
+    "@types/react": "19.2.11",
+    "@types/react-dom": "19.2.3",
+    "@vitejs/plugin-react": "5.1.3",
+    "oxfmt": "0.33.0",
+    "oxlint": "1.48.0",
+    "tailwindcss": "4.1.18",
+    "typescript": "5.9.3",
+    "vite": "7.3.1",
+    "vitest": "4.0.18"
   }
 }