Implement all main frontend views for the MITRE ATT&CK coverage platform:
- T-026: Dashboard with coverage summary cards and tactic breakdown table
- T-027: Interactive ATT&CK matrix with filtering by status, tactic, platform
- T-028: Technique detail page with tests, intel items, and review actions
- T-029: Test creation form with technique selector and validation
- T-030: Test detail page with drag and drop evidence upload and download
- T-031: System admin panel with MITRE sync and intel scan controls
New components: CoverageSummaryCard, TacticCoverageChart, AttackMatrix, TechniqueCell, TestForm, EvidenceUpload, EvidenceList
New API modules: metrics.ts, techniques.ts, tests.ts, evidence.ts, system.ts
All views use TanStack Query for data fetching with proper loading and error states. Role-based UI controls for admin/lead actions.
