refactor: consolidate plugins into plugins/ directory

- Created plugins/ directory to centralize all plugins
- Moved projman and project-hygiene into plugins/
- Updated .mcp.json paths from ../mcp-servers/ to ../../mcp-servers/
- Updated CLAUDE.md governance section with new directory structure
- Updated README.md with new repository structure diagram
- Fixed all path references in documentation

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

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

plugins/project-hygiene/hooks/hooks.json

@@ -0,0 +1,15 @@
+{
+  "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Write|Edit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/cleanup.sh"
+          }
+        ]
+      }
+    ]
+  }
+}