fix(commands): Remove deprecated 'model: sonnet' field from 142 command files

Removed the deprecated 'model: sonnet' field from command frontmatter to fix
compatibility issues with Claude Code. Commands will now inherit the model from
the active conversation instead of using a hardcoded deprecated model identifier.

Changes:
- Removed 'model: sonnet' from 142 command files across all categories
- Commands now use default model inheritance behavior
- Preserved 'model: claude-sonnet-4-5-20250929' in gemini-review.md (valid model)
- 67 commands without model field remain unchanged

This resolves the "model: sonnet not found" error reported in GitHub issues
and aligns with Claude Code's recommended practice of letting commands inherit
the conversation model.

Affected categories:
- Database/Supabase commands (8 files)
- Documentation commands (8 files)
- Deployment commands (11 files)
- Setup commands (14 files)
- Performance commands (8 files)
- Team commands (14 files)
- Security commands (6 files)
- NextJS/Vercel commands (10 files)
- Sync commands (14 files)
- And more across other categories

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: davila7