Performance chart under positions; remove obsolete files

- PerfChart moves into the left column under Open Positions
  (half-width), balancing the radar column.

Cleanup:
- Design mockup pages (DesignMockups / DesignHorizon / DesignOrbit)
  and their routes removed - the redesign has shipped; the mockups
  live on in git history. Main bundle shrinks ~97 kB and the
  chunk-size warning goes away.
- frontend/tsconfig.tsbuildinfo untracked and gitignored (incremental
  build artifact that churned in every commit).
- Dead npm test / test:watch scripts removed - vitest was never a
  dependency; CI already skips the step via its vitest guard.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/package.json

@@ -6,9 +6,7 @@
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
-    "preview": "vite preview",
-    "test": "vitest --run",
-    "test:watch": "vitest"
+    "preview": "vite preview"
   },
   "dependencies": {
     "react": "^18.3.1",