feat: FASE 1 - Backend Core (modelli, auth, API)

Implementazione completa del backend FastAPI:
- Modelli SQLAlchemy: User, Recipe, RecipeVersion, RecipeTask,
  RecipeSubtask, Measurement, AccessLog, SystemSetting, RecipeVersionAudit
- Schemas Pydantic v2 per tutti i CRUD + statistiche SPC
- Middleware: API Key auth (X-API-Key) con role checking + access logging
- Router: auth, users, recipes, tasks, measurements, files, settings
- Services: auth (bcrypt+secrets), recipe (copy-on-write versioning),
  measurement (auto pass/fail con UTL/UWL/LWL/LTL)
- Alembic env.py con import modelli attivi
- Fix architect review: no double-commit, recipe_id subquery filter,
  user_id in access logs, type annotations corrette

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

server/schemas/__init__.py

@@ -0,0 +1,81 @@
+"""Pydantic schemas for TieMeasureFlow API."""
+from schemas.measurement import (
+    MeasurementBatchCreate,
+    MeasurementCreate,
+    MeasurementListResponse,
+    MeasurementQuery,
+    MeasurementResponse,
+)
+from schemas.recipe import (
+    RecipeCreate,
+    RecipeListResponse,
+    RecipeResponse,
+    RecipeUpdate,
+    RecipeVersionResponse,
+)
+from schemas.statistics import (
+    AlertData,
+    CapabilityData,
+    ControlChartData,
+    HistogramData,
+    StatisticsQuery,
+    StatisticsResponse,
+    SummaryData,
+    TrendData,
+)
+from schemas.task import (
+    SubtaskCreate,
+    SubtaskResponse,
+    SubtaskUpdate,
+    TaskCreate,
+    TaskReorderRequest,
+    TaskResponse,
+    TaskUpdate,
+)
+from schemas.user import (
+    LoginRequest,
+    LoginResponse,
+    UserCreate,
+    UserProfileUpdate,
+    UserResponse,
+    UserUpdate,
+)
+
+__all__ = [
+    # User schemas
+    "UserCreate",
+    "UserUpdate",
+    "UserProfileUpdate",
+    "UserResponse",
+    "LoginRequest",
+    "LoginResponse",
+    # Recipe schemas
+    "RecipeCreate",
+    "RecipeUpdate",
+    "RecipeResponse",
+    "RecipeVersionResponse",
+    "RecipeListResponse",
+    # Task schemas
+    "TaskCreate",
+    "TaskUpdate",
+    "TaskResponse",
+    "TaskReorderRequest",
+    "SubtaskCreate",
+    "SubtaskUpdate",
+    "SubtaskResponse",
+    # Measurement schemas
+    "MeasurementCreate",
+    "MeasurementBatchCreate",
+    "MeasurementResponse",
+    "MeasurementListResponse",
+    "MeasurementQuery",
+    # Statistics schemas
+    "StatisticsQuery",
+    "ControlChartData",
+    "HistogramData",
+    "CapabilityData",
+    "TrendData",
+    "SummaryData",
+    "AlertData",
+    "StatisticsResponse",
+]