feat:사용자 매뉴얼 영상 자동 생성 기능 구현

- TutorialVideo 모델 (상태 관리, TenantScope)
- GeminiScriptService에 callGeminiWithParts() 멀티모달 지원 추가
- ScreenAnalysisService: Gemini Vision 스크린샷 AI 분석
- SlideAnnotationService: PHP GD 이미지 어노테이션 (마커, 캡션)
- TutorialAssemblyService: FFmpeg 이미지→영상 합성 (crossfade)
- TutorialVideoJob: 분석→슬라이드→TTS→BGM→합성 파이프라인
- TutorialVideoController: 업로드/분석/생성/상태/다운로드/이력 API
- React-in-Blade UI: 3단계 (업로드→분석확인→생성모니터링) + 이력

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Models/TutorialVideo.php

@@ -0,0 +1,69 @@
+<?php
+
+namespace App\Models;
+
+use App\Models\Scopes\TenantScope;
+use Illuminate\Database\Eloquent\Model;
+
+class TutorialVideo extends Model
+{
+    protected $fillable = [
+        'tenant_id',
+        'user_id',
+        'title',
+        'status',
+        'progress',
+        'current_step',
+        'screenshots',
+        'analysis_data',
+        'slides_data',
+        'output_path',
+        'gcs_path',
+        'cost_usd',
+        'error_message',
+    ];
+
+    protected $casts = [
+        'screenshots' => 'array',
+        'analysis_data' => 'array',
+        'slides_data' => 'array',
+        'progress' => 'integer',
+        'cost_usd' => 'decimal:4',
+    ];
+
+    protected static function booted(): void
+    {
+        static::addGlobalScope(new TenantScope);
+    }
+
+    public function user()
+    {
+        return $this->belongsTo(\App\Models\User::class);
+    }
+
+    const STATUS_PENDING = 'pending';
+    const STATUS_ANALYZING = 'analyzing';
+    const STATUS_GENERATING_SLIDES = 'generating_slides';
+    const STATUS_GENERATING_TTS = 'generating_tts';
+    const STATUS_GENERATING_BGM = 'generating_bgm';
+    const STATUS_ASSEMBLING = 'assembling';
+    const STATUS_COMPLETED = 'completed';
+    const STATUS_FAILED = 'failed';
+
+    public function updateProgress(string $status, int $progress, string $step): void
+    {
+        $this->update([
+            'status' => $status,
+            'progress' => $progress,
+            'current_step' => $step,
+        ]);
+    }
+
+    public function markFailed(string $errorMessage): void
+    {
+        $this->update([
+            'status' => self::STATUS_FAILED,
+            'error_message' => $errorMessage,
+        ]);
+    }
+}