feat(tui): add card editor

[aksOps]

Summary

• add direct-store TUI create/edit overlay with wire-valid emoji, explicit due/effort clearing, labels, checklist editing, and guarded recovery
• preserve unrelated concurrent card edits and refuse same-field conflicts
• keep debounced similar-item context generation-safe across editor sessions and mutable label exclusions
• integrate editor routing with persisted board filters, stale reload selection, dirty refresh, and mouse suppression

Verification

• targeted TUI/card detail/editor suite passed after rebase
• staged full Go, race, coverage, frontend, build, vet, format, and diff gates passed
• Go coverage: 96.6% total; 96.2% internal/tui

Closes #90

[sonarqubecloud]

Quality Gate passed

Issues
12 New issues
0 Accepted issues

Measures
0 Security Hotspots
95.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud