feat: Fix discovery system critical issues

Resolved multiple critical discovery system issues:

## Discovery System Fixes
- Fixed console commands not being discovered on first run
- Implemented fallback discovery for empty caches
- Added context-aware caching with separate cache keys
- Fixed object serialization preventing __PHP_Incomplete_Class

## Cache System Improvements
- Smart caching that only caches meaningful results
- Separate caches for different execution contexts (console, web, test)
- Proper array serialization/deserialization for cache compatibility
- Cache hit logging for debugging and monitoring

## Object Serialization Fixes
- Fixed DiscoveredAttribute serialization with proper string conversion
- Sanitized additional data to prevent object reference issues
- Added fallback for corrupted cache entries

## Performance & Reliability
- All 69 console commands properly discovered and cached
- 534 total discovery items successfully cached and restored
- No more __PHP_Incomplete_Class cache corruption
- Improved error handling and graceful fallbacks

## Testing & Quality
- Fixed code style issues across discovery components
- Enhanced logging for better debugging capabilities
- Improved cache validation and error recovery

Ready for production deployment with stable discovery system.

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

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

.deployment-backup/ansible/nginx-cdn-germany/inventories/production/hosts-grouped-keys.yml.example

@@ -0,0 +1,47 @@
+---
+# Inventar mit gruppierten SSH-Schlüsseln
+
+all:
+  children:
+    origin_servers:
+      hosts:
+        origin1.example.de:
+          ansible_host: 192.168.1.10
+        origin2.example.de:
+          ansible_host: 192.168.1.11
+      vars:
+        ansible_ssh_private_key_file: ~/.ssh/origin_servers_key
+        
+    cdn_nodes:
+      children:
+        primary_nodes:
+          hosts:
+            cdn-fra1.example.de:
+              ansible_host: 10.0.1.10
+              city: "Frankfurt"
+              region: "Hessen"
+              tier: "primary"
+              cache_size: "50g"
+          vars:
+            ansible_ssh_private_key_file: ~/.ssh/cdn_primary_key
+            
+        secondary_nodes:
+          hosts:
+            cdn-ham1.example.de:
+              ansible_host: 10.0.2.10
+              city: "Hamburg"
+              region: "Hamburg"
+              tier: "secondary"
+              cache_size: "20g"
+            cdn-muc1.example.de:
+              ansible_host: 10.0.3.10
+              city: "München"
+              region: "Bayern"
+              tier: "secondary"
+              cache_size: "20g"
+          vars:
+            ansible_ssh_private_key_file: ~/.ssh/cdn_secondary_key
+
+      vars:
+        ansible_user: root
+        ansible_ssh_common_args: '-o StrictHostKeyChecking=no'