[Change] Spec-Kit v0.4.x Adapter Alignment

[djm81]

Change Proposal: speckit-02-v04-adapter-alignment

Change folder: openspec/changes/speckit-02-v04-adapter-alignment/

Why

GitHub Spec-Kit has advanced to v0.4.3 with 46 community extensions, a pluggable preset system, 7+ slash commands, hook events, and auto-registered AI skills. Our SpecKitAdapter was built against the initial spec-kit layout and no longer models the tool's actual capabilities, creating silent drift in sync operations.

What Changes

• Expand BridgeConfig presets to map all 7 spec-kit slash commands (was 2)
• Add extension catalog awareness (detect extensions/, parse catalogs, model extension commands)
• Implement version detection (CLI probe + directory heuristics)
• Add preset system detection (scan presets/ directory)
• Model hook events for sync coordination
• Expand ToolCapabilities dataclass with extension/preset/hook metadata
• Add .extensionignore support

Capabilities

• New: speckit-extension-catalog, speckit-version-detection
• Modified: bridge-adapter, bridge-registry

Impact

• 4 files modified: adapters/speckit.py, models/capabilities.py, models/bridge.py, importers/speckit_scanner.py
• Enables downstream: sync-01-unified-kernel (#243), requirements-03-backlog-sync (Requirements ↔ Backlog Bidirectional Sync #244), speckit-03 (modules repo)

Blocked By

None (standalone adapter update)

Validation

• ✅ openspec validate --strict passed
• ✅ No breaking changes detected (all additive)
• See CHANGE_VALIDATION.md in change folder