docs: Create comprehensive agents.md and deprecate .clinerules

- Added docs/agents.md with complete repository guide
- Includes all project structure, workflows, testing procedures
- Covers package management, security, rollback procedures
- Added maintenance section with changelog for future updates
- Deprecated .clinerules, pointing to agents.md instead
- Created single source of truth for AI agent operations

.clinerules

@@ -1,7 +1,18 @@
+# DEPRECATED - Use docs/agents.md instead
+
+This file is deprecated. All project-specific rules, guidelines, and documentation for AI agents have been moved to:
+**`docs/agents.md`**
+
+The new file is more comprehensive and actively maintained. Please use it instead of this file for all AI agent operations.
+
+---
+
 # NixOS Configuration Repository - AI Agent Guidelines
 
 This file contains project-specific rules and guidelines for AI agents working with this NixOS configuration repository. Follow these rules to ensure consistent, secure, and maintainable configurations.
 
+**Note:** The content below is deprecated. See `docs/agents.md` for the latest information.
+
 ## Core Principles
 
 ### 1. Declarative Configuration
@@ -262,6 +273,7 @@ nix flake show
 - Reference affected systems/modules
 - Explain reasoning for significant changes
 - Include testing steps when applicable
+- **Update docs/agents.md changelog** when making structural or procedural changes
 
 ## Emergency Procedures
 
@@ -301,9 +313,10 @@ sudo nixos-rebuild switch --rollback
 
 ### After Changes
 1. **Run complete test suite**
-2. **Update relevant documentation**
-3. **Verify all systems** build successfully
-4. **Commit with clear message** describing changes
+2. **Update `docs/agents.md`** if repository structure or procedures changed
+3. **Update relevant documentation**
+4. **Verify all systems** build successfully
+5. **Commit with clear message** describing changes
 
 ---