docs: add plugin commands cheat sheet with workflow examples

Add comprehensive documentation for all marketplace plugin commands:
- Reference table with all 37 commands across 9 plugins
- Auto vs manual trigger indicators
- 7 dev workflow examples for practical usage
- Hook-based automation summary
- MCP server requirements

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/CANONICAL-PATHS.md

@@ -155,6 +155,7 @@ The symlink target is relative: `../../../mcp-servers/{server}`
 | This file | `docs/CANONICAL-PATHS.md` |
 | Update guide | `docs/UPDATING.md` |
 | Configuration guide | `docs/CONFIGURATION.md` |
+| Commands cheat sheet | `docs/COMMANDS-CHEATSHEET.md` |
 
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