feat: add per-space timezone settings and improve booking management

- Add timezone configuration per space with fallback to system default
- Implement timezone-aware datetime display and editing across frontend
- Add migration for per_space_settings table
- Update booking service to handle timezone conversions properly
- Improve .gitignore to exclude build artifacts
- Add comprehensive testing documentation

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/app/models/__init__.py

@@ -3,9 +3,10 @@ from app.models.attachment import Attachment
 from app.models.audit_log import AuditLog
 from app.models.booking import Booking
 from app.models.booking_template import BookingTemplate
+from app.models.google_calendar_token import GoogleCalendarToken
 from app.models.notification import Notification
 from app.models.settings import Settings
 from app.models.space import Space
 from app.models.user import User
 
-__all__ = ["User", "Space", "Settings", "Booking", "BookingTemplate", "Notification", "AuditLog", "Attachment"]
+__all__ = ["User", "Space", "Settings", "Booking", "BookingTemplate", "Notification", "AuditLog", "Attachment", "GoogleCalendarToken"]

backend/app/models/space.py

@@ -15,3 +15,9 @@ class Space(Base):
     capacity = Column(Integer, nullable=False)
     description = Column(String, nullable=True)
     is_active = Column(Boolean, default=True, nullable=False)
+
+    # Per-space scheduling settings (NULL = use global default)
+    working_hours_start = Column(Integer, nullable=True)
+    working_hours_end = Column(Integer, nullable=True)
+    min_duration_minutes = Column(Integer, nullable=True)
+    max_duration_minutes = Column(Integer, nullable=True)