Adds a View button (eye icon) on each evidence card for previewable file
types. Opens a full-screen modal:
- Images (png/jpg/gif/webp/svg/…): rendered directly via <img> tag
- JSON: fetched authenticated, pretty-printed in green mono
- Text/log/md/csv/xml/yaml/…: fetched authenticated, shown in <pre>
Non-previewable files only show the Download button as before.
Modal closes on Escape or backdrop click.
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.