[Extension]: Add spec-kit-switch

### Extension ID
switch

### Extension Name
Spec Switcher

### Version
1.0.0

### Description
Navigate between specs — list available specs and switch active feature with git checkout

### Author
Wagner Sousa

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

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

### License
MIT

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

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

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

### Required Spec Kit Version
>=0.4.0

### Number of Commands
2

### Number of Hooks
0

### Tags
navigation, workflow, specs, sdd, git

### Key Features
- List all available specs with branch and active status in a table
- Switch between specs via git checkout (avoids feature.json conflicts)
- Auto-unlock previous spec lifecycle on switch via cross-plugin interface
- --local-only flag for branchless specs

### 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. Both commands verified: switch.list shows all specs with branch/status table, switch.set performs git checkout with auto-unlock of previous spec. Cross-plugin interface tested with lifecycle extension for seamless spec transitions.

### Example Usage
```bash
specify extension add switch --from https://github.com/wagner-sousa/spec-kit-switch/archive/refs/tags/v1.0.0.zip
/speckit.switch.list
/speckit.switch.set 013
```

### Proposed Catalog Entry
```json
{
"switch": {
"name": "Spec Switcher",
"id": "switch",
"description": "Navigate between specs — list available specs and switch active feature with git checkout",
"author": "Wagner Sousa",
"version": "1.0.0",
"download_url": "https://github.com/wagner-sousa/spec-kit-switch/archive/refs/tags/v1.0.0.zip",
"repository": "https://github.com/wagner-sousa/spec-kit-switch",
"homepage": "https://github.com/wagner-sousa/spec-kit-switch",
"license": "MIT",
"requires": {
"speckit_version": ">=0.4.0"
},
"provides": {
"commands": 2
},
"tags": ["navigation", "workflow", "specs", "sdd", "git"],
"verified": false,
"downloads": 0,
"stars": 0,
"created_at": "2026-07-31T00:00:00Z",
"updated_at": "2026-07-31T00:00:00Z"
}
}
```

Revise a entrada de catálogo proposta, o manifesto extension.yml, README.md e LICENSE do repositório da extensão vinculada. Comece localizando o catálogo de extensões do repositório e suas verificações de validação. A tarefa estará concluída quando os metadados do Spec Switcher forem adicionados corretamente e o catálogo continuar sendo validado.

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