feat: Add Official Microsoft & Gemini Skills (845+ Total)

🚀 Impact

Significantly expands the capabilities of **Antigravity Awesome Skills** by integrating official skill collections from **Microsoft** and **Google Gemini**. This update increases the total skill count to **845+**, making the library even more comprehensive for AI coding assistants.

✨ Key Changes

1. New Official Skills

- **Microsoft Skills**: Added a massive collection of official skills from [microsoft/skills](https://github.com/microsoft/skills).
  - Includes Azure, .NET, Python, TypeScript, and Semantic Kernel skills.
  - Preserves the original directory structure under `skills/official/microsoft/`.
  - Includes plugin skills from the `.github/plugins` directory.
- **Gemini Skills**: Added official Gemini API development skills under `skills/gemini-api-dev/`.

2. New Scripts & Tooling

- **`scripts/sync_microsoft_skills.py`**: A robust synchronization script that:
  - Clones the official Microsoft repository.
  - Preserves the original directory heirarchy.
  - Handles symlinks and plugin locations.
  - Generates attribution metadata.
- **`scripts/tests/inspect_microsoft_repo.py`**: Debug tool to inspect the remote repository structure.
- **`scripts/tests/test_comprehensive_coverage.py`**: Verification script to ensure 100% of skills are captured during sync.

3. Core Improvements

- **`scripts/generate_index.py`**: Enhanced frontmatter parsing to safely handle unquoted values containing `@` symbols and commas (fixing issues with some Microsoft skill descriptions).
- **`package.json`**: Added `sync:microsoft` and `sync:all-official` scripts for easy maintenance.

4. Documentation

- Updated `README.md` to reflect the new skill counts (845+) and added Microsoft/Gemini to the provider list.
- Updated `CATALOG.md` and `skills_index.json` with the new skills.

🧪 Verification

- Ran `scripts/tests/test_comprehensive_coverage.py` to verify all Microsoft skills are detected.
- Validated `generate_index.py` fixes by successfully indexing the new skills.

skills/official/microsoft/plugins/wiki-changelog/SKILL.md

@@ -0,0 +1,27 @@
+---
+name: wiki-changelog
+description: Analyzes git commit history and generates structured changelogs categorized by change type. Use when the user asks about recent changes, wants a changelog, or needs to understand what changed in the repository.
+---
+
+# Wiki Changelog
+
+Generate structured changelogs from git history.
+
+## When to Activate
+
+- User asks "what changed recently", "generate a changelog", "summarize commits"
+- User wants to understand recent development activity
+
+## Procedure
+
+1. Examine git log (commits, dates, authors, messages)
+2. Group by time period: daily (last 7 days), weekly (older)
+3. Classify each commit: Features (🆕), Fixes (🐛), Refactoring (🔄), Docs (📝), Config (🔧), Dependencies (📦), Breaking (⚠️)
+4. Generate concise user-facing descriptions using project terminology
+
+## Constraints
+
+- Focus on user-facing changes
+- Merge related commits into coherent descriptions
+- Use project terminology from README
+- Highlight breaking changes prominently with migration notes