[Extension]: Add spec-kit-lifecycle

### Extension ID
lifecycle

### Extension Name
SDD Lifecycle Manager

### Version
1.0.0

### Description
Phase-gate lifecycle for Spec Kit — lock spec artifacts after finalization, block destructive commands, allow only refine/bugfix

### Author
Wagner Sousa

### Repository URL
https://github.com/wagner-sousa/spec-kit-lifecycle

### Download URL
https://github.com/wagner-sousa/spec-kit-lifecycle/archive/refs/tags/v1.0.0.zip

### License
MIT

### Homepage
https://github.com/wagner-sousa/spec-kit-lifecycle

### Documentation URL
https://github.com/wagner-sousa/spec-kit-lifecycle#readme

### Changelog URL
https://github.com/wagner-sousa/spec-kit-lifecycle/blob/main/CHANGELOG.md

### Required Spec Kit Version
>=0.4.0

### Number of Commands
5

### Number of Hooks
2

### Tags
lifecycle, governance, gates, workflow, sdd

### Key Features
- Lock spec artifacts after finalization to prevent accidental modifications
- Block destructive SDD commands (specify, clarify, plan, tasks, checklist, analyze) when locked
- Allow controlled paths (refine.*, bugfix.*) during locked phase
- Per-spec lifecycle state stored in specs/NNN-feature/.lifecycle.json
- Mandatory before_* hooks for core SDD commands
- Cross-plugin interface: unlock --spec-dir for external plugins
- Auto-sync lock status to AGENTS.md via write-agents command
- Configurable blocked/allowed commands via lifecycle-config.yml

### Testing Checklist
- [x] Extension installs successfully via download URL
- [x] All commands execute without errors
- [x] Documentation is complete and accurate
- [x] No security vulnerabilities identified
- [x] Tested on at least one real project

### Submission Requirements
- [x] Valid `extension.yml` manifest included
- [x] README.md with installation and usage instructions
- [x] LICENSE file included
- [x] GitHub release created with version tag
- [x] All command files exist and are properly formatted
- [x] Extension ID follows naming conventions (lowercase-with-hyphens)

### Testing Details
Tested on Linux with Spec Kit v0.13.3 in the spec-kit-docker template project. All commands verified: check blocks locked specs, lock/unlock toggle lifecycle state, status displays phase info, write-agents syncs to AGENTS.md. Cross-plugin interface tested with switch extension auto-unlock on spec checkout.

### Example Usage
```bash
specify extension add lifecycle --from https://github.com/wagner-sousa/spec-kit-lifecycle/archive/refs/tags/v1.0.0.zip
/speckit.lifecycle.lock
/speckit.lifecycle.status
/speckit.lifecycle.unlock --spec-dir specs/013-fix-auth
```

### Proposed Catalog Entry
```json
{
"lifecycle": {
"name": "SDD Lifecycle Manager",
"id": "lifecycle",
"description": "Phase-gate lifecycle for Spec Kit — lock spec artifacts after finalization, block destructive commands, allow only refine/bugfix",
"author": "Wagner Sousa",
"version": "1.0.0",
"download_url": "https://github.com/wagner-sousa/spec-kit-lifecycle/archive/refs/tags/v1.0.0.zip",
"repository": "https://github.com/wagner-sousa/spec-kit-lifecycle",
"homepage": "https://github.com/wagner-sousa/spec-kit-lifecycle",
"license": "MIT",
"requires": {
"speckit_version": ">=0.4.0"
},
"provides": {
"commands": 5,
"hooks": 2
},
"tags": ["lifecycle", "governance", "gates", "workflow", "sdd"],
"verified": false,
"downloads": 0,
"stars": 0,
"created_at": "2026-07-31T00:00:00Z",
"updated_at": "2026-07-31T00:00:00Z"
}
}
```