v0.26.0: Skills system, session favorites, and improved git integration

New features

- Skills System - Claude Code-compatible .factory/skills support for modular, prompt-based capabilities. Use the /skills command to manage skills and import from .claude/skills directories
- Session Favorites - New /favorite command to pin/unpin sessions, keeping your active projects at the top of the session list
- Enhanced Bug Reporting - The /bug command now zips session context, uploads it to Factory, and returns a shareable report ID automatically
- Cleaner Diff Viewer - Improved UI with horizontal lines instead of borders

Bug fixes

- Always prompt to accept or reject generated specs and pass the correct labels to the UI flow
- droid spec now writes files to the expected default path without manual overrides
- Fixed autonomy handling so MCP tools respect the configured confirmation level in every session
- Better error handling in pre-update logic
- Added Axiom MCP server to the registry