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/Migrations/CreateJobAssignmentsTable.php

@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\Queue\Migrations;
+
+use App\Framework\Database\ConnectionInterface;
+use App\Framework\Database\Migration\Migration;
+use App\Framework\Database\Migration\MigrationVersion;
+use App\Framework\Database\Schema\Schema;
+
+/**
+ * Migration für Job Assignments Tabelle
+ */
+final readonly class CreateJobAssignmentsTable implements Migration
+{
+    public function up(ConnectionInterface $connection): void
+    {
+        $schema = new Schema($connection);
+
+        $schema->createIfNotExists('job_assignments', function ($table) {
+            // Job ID - eindeutige Zuordnung
+            $table->string('job_id', 32)->primary();
+
+            // Worker der den Job verarbeitet
+            $table->string('worker_id', 32);
+
+            // Queue Name für Statistiken
+            $table->string('queue_name', 255);
+
+            // Assignment Timestamp
+            $table->timestamp('assigned_at')->default('CURRENT_TIMESTAMP');
+
+            // Indexes
+            $table->index('worker_id', 'idx_assignment_worker');
+            $table->index('queue_name', 'idx_assignment_queue');
+            $table->index(['worker_id', 'assigned_at'], 'idx_assignment_worker_time');
+            $table->index('assigned_at', 'idx_assignment_time');
+        });
+
+        $schema->execute();
+    }
+
+    public function down(ConnectionInterface $connection): void
+    {
+        $schema = new Schema($connection);
+        $schema->dropIfExists('job_assignments');
+        $schema->execute();
+    }
+
+    public function getVersion(): MigrationVersion
+    {
+        return MigrationVersion::fromTimestamp("2024_12_19_145000");
+    }
+
+    public function getDescription(): string
+    {
+        return 'Create job_assignments table for tracking job-to-worker assignments';
+    }
+
+    public function getDomain(): string
+    {
+        return "Framework";
+    }
+}