feat: Space Booking System - MVP complet

Sistem web pentru rezervarea de birouri și săli de ședință
cu flux de aprobare administrativă.

Stack: FastAPI + Vue.js 3 + SQLite + TypeScript

Features implementate:
- Autentificare JWT + Self-registration cu email verification
- CRUD Spații, Utilizatori, Settings (Admin)
- Calendar interactiv (FullCalendar) cu drag-and-drop
- Creare rezervări cu validare (durată, program, overlap, max/zi)
- Rezervări recurente (săptămânal)
- Admin: aprobare/respingere/anulare cereri
- Admin: creare directă rezervări (bypass approval)
- Admin: editare orice rezervare
- User: editare/anulare rezervări proprii
- Notificări in-app (bell icon + dropdown)
- Notificări email (async SMTP cu BackgroundTasks)
- Jurnal acțiuni administrative (audit log)
- Rapoarte avansate (utilizare, top users, approval rate)
- Șabloane rezervări (booking templates)
- Atașamente fișiere (upload/download)
- Conflict warnings (verificare disponibilitate real-time)
- Integrare Google Calendar (OAuth2)
- Suport timezone (UTC storage + user preference)
- 225+ teste backend

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

backend/app/models/booking.py

@@ -0,0 +1,36 @@
+"""Booking model."""
+from datetime import datetime
+
+from sqlalchemy import Column, DateTime, ForeignKey, Integer, String
+from sqlalchemy.orm import relationship
+
+from app.db.session import Base
+
+
+class Booking(Base):
+    """Booking model for space reservations."""
+
+    __tablename__ = "bookings"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False, index=True)
+    space_id = Column(Integer, ForeignKey("spaces.id"), nullable=False, index=True)
+    title = Column(String, nullable=False)
+    description = Column(String, nullable=True)
+    start_datetime = Column(DateTime, nullable=False, index=True)
+    end_datetime = Column(DateTime, nullable=False, index=True)
+    status = Column(
+        String, nullable=False, default="pending", index=True
+    )  # pending/approved/rejected/canceled
+    rejection_reason = Column(String, nullable=True)
+    cancellation_reason = Column(String, nullable=True)
+    approved_by = Column(Integer, ForeignKey("users.id"), nullable=True)
+    google_calendar_event_id = Column(String, nullable=True)  # Store Google Calendar event ID
+    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
+
+    # Relationships
+    user = relationship("User", foreign_keys=[user_id], backref="bookings")
+    space = relationship("Space", foreign_keys=[space_id], backref="bookings")
+    approver = relationship("User", foreign_keys=[approved_by], backref="approved_bookings")
+    notifications = relationship("Notification", back_populates="booking")
+    attachments = relationship("Attachment", back_populates="booking", cascade="all, delete-orphan")