feat(frontend): slice 1 — foundation for MUI->shadcn migration

Web UI rework (openspec/changes/web-ui-rework). Foundation slice:
- Add @tanstack/react-table; remove orphaned recharts, d3
- Vendor shadcn primitives: tabs table dialog input label checkbox
  switch progress separator avatar textarea dropdown-menu scroll-area
- Add Vitest + @testing-library/react + jsdom harness; npm test script
- Delete no-op theme.ts shim; remove getAppTheme references
- Smoke test proves the harness

Gate: build + lint + test green.

frontend/package.json

@@ -7,7 +7,10 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "eslint .",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:node": "node --test tests/*.test.mjs"
   },
   "dependencies": {
     "@emotion/react": "^11.14.0",
@@ -17,9 +20,9 @@
     "@mui/material": "^9.0.0",
     "@mui/x-data-grid": "^9.0.4",
     "@tanstack/react-query": "^5.100.6",
+    "@tanstack/react-table": "^8.21.3",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
-    "d3": "^7.9.0",
     "lucide-react": "^1.14.0",
     "oidc-client-ts": "^3.5.0",
     "radix-ui": "^1.4.3",
@@ -27,7 +30,6 @@
     "react-dom": "^19.2.5",
     "react-oidc-context": "^3.3.1",
     "react-router-dom": "^7.14.2",
-    "recharts": "^3.8.1",
     "shadcn": "^4.7.0",
     "tailwind-merge": "^3.6.0",
     "tw-animate-css": "^1.4.0"
@@ -36,7 +38,9 @@
     "@eslint/js": "^10.0.1",
     "@tailwindcss/postcss": "^4.3.0",
     "@tailwindcss/vite": "^4.3.0",
-    "@types/d3": "^7.4.3",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
     "@types/node": "^24.13.2",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
@@ -46,10 +50,12 @@
     "eslint-plugin-react-hooks": "^7.1.1",
     "eslint-plugin-react-refresh": "^0.5.2",
     "globals": "^17.5.0",
+    "jsdom": "^29.1.1",
     "postcss": "^8.5.14",
     "tailwindcss": "^4.3.0",
     "typescript": "~6.0.2",
     "typescript-eslint": "^8.58.2",
-    "vite": "^8.0.10"
+    "vite": "^8.0.10",
+    "vitest": "^4.1.9"
   }
 }