[Extension]: Jira Integration (Sync Engine) v0.5.0 (version update of jira-sync)

> **Note for triage:** version update of the existing catalog entry `jira-sync` → `0.5.0` (re-filed via this template per the maintainer process; direct-JSON catalog PRs are now redirected here).

### Extension ID
jira-sync

### Extension Name
Jira Integration (Sync Engine)

### Version
0.5.0

### Description
An idempotent, drift-aware, fail-closed reconcile engine that mirrors spec-kit specs into Jira (Epic per repo, Story per spec, Subtask per phase).

### Author
Ash Brener

### Repository URL
https://github.com/ashbrener/spec-kit-jira-sync

### Download URL
https://github.com/ashbrener/spec-kit-jira-sync/archive/refs/tags/v0.5.0.zip

### License
MIT

### Homepage (optional)
https://github.com/ashbrener/spec-kit-jira-sync

### Documentation URL (optional)
https://github.com/ashbrener/spec-kit-jira-sync/blob/main/README.md

### Changelog URL (optional)
https://github.com/ashbrener/spec-kit-jira-sync/blob/main/CHANGELOG.md

### Required Spec Kit Version
>=0.1.0

### Number of Commands
4

### Tags
issue-tracking, jira, tasks-sync, reconcile, drift-aware

### 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
Released `v0.5.0` with a published source archive (pre-flight verified HTTP 200 at the download URL). Full offline test suite (bats + shellcheck + yamllint + markdownlint) green in CI on macOS + Linux; dogfooded against a live Jira project.

### Example Usage
```bash
specify extension add jira-sync --from https://github.com/ashbrener/spec-kit-jira-sync/archive/refs/tags/v0.5.0.zip
```

### Proposed Catalog Entry
```json
{
"jira-sync": {
"name": "Jira Integration (Sync Engine)",
"id": "jira-sync",
"description": "An idempotent, drift-aware, fail-closed reconcile engine that mirrors spec-kit specs into Jira (Epic per repo, Story per spec, Subtask per phase).",
"author": "Ash Brener",
"version": "0.5.0",
"download_url": "https://github.com/ashbrener/spec-kit-jira-sync/archive/refs/tags/v0.5.0.zip",
"repository": "https://github.com/ashbrener/spec-kit-jira-sync",
"homepage": "https://github.com/ashbrener/spec-kit-jira-sync",
"documentation": "https://github.com/ashbrener/spec-kit-jira-sync/blob/main/README.md",
"changelog": "https://github.com/ashbrener/spec-kit-jira-sync/blob/main/CHANGELOG.md",
"license": "MIT",
"requires": { "speckit_version": ">=0.1.0" },
"provides": { "commands": 4, "hooks": 0 },
"tags": ["issue-tracking", "jira", "tasks-sync", "reconcile", "drift-aware"],
"verified": false,
"downloads": 0,
"stars": 0,
"updated_at": "2026-08-12T00:00:00Z"
}
}
```

### Additional Context
Version bump of the existing `jira-sync` entry; only `version`, `download_url`, `provides.commands`, and `updated_at` change. Preserve the existing `created_at`. Thanks for maintaining the catalog!

既存の jira-sync カタログエントリを見つけ、この issue で提案されているカタログエントリと比較します。created_at を保持したまま、version、download URL、command count、updated_at のみを更新し、その後カタログの検証チェックを実行して、エントリが引き続き有効であることを確認します。

索引モデルが issue の本文から書いたものです。