AI provider management

* OpenAI-compatible provider adapter
* OpenAI support
* LM Studio support
* Ollama OpenAI-compatible support
* Encrypted API-key storage
* Default provider and model selection
* Provider connection testing
* Reusable prompt library
* Prompt variables and templates
* Prompt version field
* AI execution history
* Token-usage storage
* Duration and failure tracking
* Manual knowledge sources
* Knowledge-source chunking
* Knowledge indexing status
* Authenticated AI REST endpoint
* AI administration dashboard
* AI permissions
* Module registration and boot test

Modules/AI/Models/AIKnowledgeChunk.php

@@ -0,0 +1,8 @@
+<?php
+namespace Modules\AI\Models;
+use Illuminate\Database\Eloquent\Model;
+final class AIKnowledgeChunk extends Model
+{
+    protected $fillable=['ai_knowledge_source_id','position','content','metadata'];
+    protected $casts=['metadata'=>'array'];
+}