feat: add doc-guardian plugin for documentation lifecycle management

Adds automatic documentation drift detection and synchronization:
- PostToolUse hook detects when code changes affect docs
- Stop hook reminds of pending updates before session ends
- /doc-audit command for full project documentation scan
- /doc-sync command to batch apply pending updates
- doc-analyzer agent for cross-reference analysis
- doc-patterns skill for documentation structure knowledge

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

plugins/doc-guardian/.claude-plugin/plugin.json

@@ -0,0 +1,13 @@
+{
+  "name": "doc-guardian",
+  "description": "Automatic documentation drift detection and synchronization",
+  "version": "1.0.0",
+  "author": {
+    "name": "Leo Miranda",
+    "email": "leobmiranda@gmail.com"
+  },
+  "homepage": "https://gitea.hotserv.cloud/personal-projects/support-claude-mktplace/src/branch/main/plugins/doc-guardian/README.md",
+  "repository": "https://gitea.hotserv.cloud/personal-projects/support-claude-mktplace.git",
+  "license": "MIT",
+  "keywords": ["documentation", "sync", "drift-detection", "automation", "hooks"]
+}