refactor: rename marketplace to bandit-claude-marketplace

- Changed marketplace name from projman-marketplace to bandit-claude-marketplace
- Updated all references in:
  - .claude-plugin/marketplace.json
  - README.md (installation instructions, structure diagram)
  - docs/CANONICAL-PATHS.md (structure and path examples)
- Cleaned up documentation to reflect correct marketplace location at repo root

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

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

.claude-plugin/marketplace.json

@@ -1,5 +1,5 @@
 {
-  "name": "projman-marketplace",
+  "name": "bandit-claude-marketplace",
   "version": "1.0.0",
   "description": "Project management plugins with Gitea, Wiki.js, and NetBox integrations",
   "owner": {