feat(p2p): add Phase 3 dispute system components

- Add DisputeModal.tsx with reason selection, evidence upload, terms acceptance
- Add P2PDispute.tsx page with evidence gallery, status timeline, real-time updates
- Integrate dispute button in P2PTrade.tsx
- Add /p2p/dispute/:disputeId route to App.tsx
- Add P2P test suite with MockStore pattern (32 tests passing)
- Update P2P-BUILDING-PLAN.md with Phase 3 progress (70% complete)
- Fix lint errors in test files and components

web/public/docs-structure.json

@@ -27,9 +27,5 @@
     "SECURITY": "contributor/SECURITY.md",
     "STYLE GUIDE": "contributor/STYLE_GUIDE.md",
     "Weight Generation": "contributor/weight-generation.md"
-  },
-  "Whitepaper": {
-    "Whitepaper": "whitepaper/whitepaper.md"
-  },
-  "Introduction": "introduction.md"
+  }
 }