docs: consolidate documentation into organized structure

- Move 12 markdown files from root to docs/ subdirectories
- Organize documentation by category:
  • docs/troubleshooting/ (1 file)  - Technical troubleshooting guides
  • docs/deployment/      (4 files) - Deployment and security documentation
  • docs/guides/          (3 files) - Feature-specific guides
  • docs/planning/        (4 files) - Planning and improvement proposals

Root directory cleanup:
- Reduced from 16 to 4 markdown files in root
- Only essential project files remain:
  • CLAUDE.md (AI instructions)
  • README.md (Main project readme)
  • CLEANUP_PLAN.md (Current cleanup plan)
  • SRC_STRUCTURE_IMPROVEMENTS.md (Structure improvements)

This improves:
✅ Documentation discoverability
✅ Logical organization by purpose
✅ Clean root directory
✅ Better maintainability

src/Framework/Queue/Events/JobChainStartedEvent.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\Queue\Events;
+
+use App\Framework\Queue\ValueObjects\ChainExecutionMode;
+use App\Framework\Core\ValueObjects\Timestamp;
+
+final readonly class JobChainStartedEvent
+{
+    public Timestamp $timestamp;
+
+    public function __construct(
+        public string $chainId,
+        public string $name,
+        public ChainExecutionMode $executionMode,
+        public array $jobIds,
+        ?Timestamp $timestamp = null
+    ) {
+        $this->timestamp = $timestamp ?? Timestamp::now();
+    }
+
+    public function getEventData(): array
+    {
+        return [
+            'event_type' => 'job_chain_started',
+            'chain_id' => $this->chainId,
+            'name' => $this->name,
+            'execution_mode' => $this->executionMode->value,
+            'job_ids' => $this->jobIds,
+            'job_count' => count($this->jobIds),
+            'timestamp' => $this->timestamp->toFloat()
+        ];
+    }
+}