feat: добавить отзывы, milestone-платежи, портфолио, skill-tests и верификацию (фичи Upwork/Fiverr)

Фичи конкурентов внедрены:
- Reviews API + UI — система отзывов с рейтингом 1-5 звёзд
- Milestones (Upwork-style) — разделение escrow на этапы с submit/approve
- Portfolio — портфолио фрилансера с превью работ и технологиями
- Skill Tests (Upwork-style) — сертификация навыков с тестами
- Verification Badges — верификация email/phone/id/bank

Модели: Milestone, PortfolioItem, SkillTest/SkillTestResult, Verification

backend/app/main.py

@@ -12,6 +12,11 @@ from app.api.projects import router as projects_router
 from app.api.proposals import router as proposals_router
 from app.api.ai import router as ai_router
 from app.api.escrow import router as escrow_router
+from app.api.reviews import router as reviews_router
+from app.api.milestones import router as milestones_router
+from app.api.portfolio import router as portfolio_router
+from app.api.skill_tests import router as skill_tests_router
+from app.api.verification import router as verification_router
 
 logging.basicConfig(level=logging.INFO)
 
@@ -46,6 +51,11 @@ app.include_router(projects_router)
 app.include_router(proposals_router)
 app.include_router(ai_router)
 app.include_router(escrow_router)
+app.include_router(reviews_router)
+app.include_router(milestones_router)
+app.include_router(portfolio_router)
+app.include_router(skill_tests_router)
+app.include_router(verification_router)
 
 
 @app.get("/api/health")