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/Performance/Entity/PerformanceMetric.php

@@ -0,0 +1,108 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\Performance\Entity;
+
+use App\Framework\Core\ValueObjects\Byte;
+use App\Framework\Core\ValueObjects\Duration;
+use App\Framework\Database\Migration\MigrationVersion;
+use App\Framework\Performance\PerformanceCategory;
+use DateTimeImmutable;
+
+final readonly class PerformanceMetric
+{
+    public function __construct(
+        public ?int $id,
+        public string $operationId,
+        public string $operationType,
+        public PerformanceCategory $category,
+        public ?MigrationVersion $migrationVersion,
+        public Duration $executionTime,
+        public Byte $memoryStart,
+        public Byte $memoryEnd,
+        public Byte $memoryPeak,
+        public Byte $memoryDelta,
+        public bool $success,
+        public ?string $errorMessage,
+        public ?array $metadata,
+        public DateTimeImmutable $createdAt,
+        public ?DateTimeImmutable $updatedAt = null
+    ) {
+    }
+
+    public static function fromPerformanceSnapshot(
+        string $operationId,
+        string $operationType,
+        PerformanceCategory $category,
+        Duration $executionTime,
+        Byte $memoryStart,
+        Byte $memoryEnd,
+        Byte $memoryPeak,
+        Byte $memoryDelta,
+        bool $success = true,
+        ?string $errorMessage = null,
+        ?MigrationVersion $migrationVersion = null,
+        ?array $metadata = null
+    ): self {
+        return new self(
+            id: null,
+            operationId: $operationId,
+            operationType: $operationType,
+            category: $category,
+            migrationVersion: $migrationVersion,
+            executionTime: $executionTime,
+            memoryStart: $memoryStart,
+            memoryEnd: $memoryEnd,
+            memoryPeak: $memoryPeak,
+            memoryDelta: $memoryDelta,
+            success: $success,
+            errorMessage: $errorMessage,
+            metadata: $metadata,
+            createdAt: new DateTimeImmutable(),
+            updatedAt: null
+        );
+    }
+
+    public function toArray(): array
+    {
+        return [
+            'id' => $this->id,
+            'operation_id' => $this->operationId,
+            'operation_type' => $this->operationType,
+            'category' => $this->category->value,
+            'migration_version' => $this->migrationVersion?->toString(),
+            'execution_time_ms' => $this->executionTime->toMilliseconds(),
+            'memory_start_bytes' => $this->memoryStart->toBytes(),
+            'memory_end_bytes' => $this->memoryEnd->toBytes(),
+            'memory_peak_bytes' => $this->memoryPeak->toBytes(),
+            'memory_delta_bytes' => $this->memoryDelta->toBytes(),
+            'success' => $this->success,
+            'error_message' => $this->errorMessage,
+            'metadata' => $this->metadata ? json_encode($this->metadata) : null,
+            'created_at' => $this->createdAt->format('Y-m-d H:i:s'),
+            'updated_at' => $this->updatedAt?->format('Y-m-d H:i:s'),
+        ];
+    }
+
+    public static function fromArray(array $data): self
+    {
+        return new self(
+            id: $data['id'] ?? null,
+            operationId: $data['operation_id'],
+            operationType: $data['operation_type'],
+            category: PerformanceCategory::from($data['category']),
+            migrationVersion: $data['migration_version'] ? MigrationVersion::fromTimestamp($data['migration_version']) : null,
+            executionTime: Duration::fromMilliseconds($data['execution_time_ms']),
+            memoryStart: Byte::fromBytes($data['memory_start_bytes']),
+            memoryEnd: Byte::fromBytes($data['memory_end_bytes']),
+            memoryPeak: Byte::fromBytes($data['memory_peak_bytes']),
+            memoryDelta: Byte::fromBytes($data['memory_delta_bytes']),
+            success: (bool) $data['success'],
+            errorMessage: $data['error_message'],
+            metadata: $data['metadata'] ? json_decode($data['metadata'], true) : null,
+            createdAt: new DateTimeImmutable($data['created_at']),
+            updatedAt: $data['updated_at'] ? new DateTimeImmutable($data['updated_at']) : null
+        );
+    }
+}