feat: Add Chat UX improvements with notifications and @mention support

- Add ActionBar component with expandable toolbar for mobile
- Add @mention functionality with autocomplete dropdown
- Add browser notification system (push, sound, vibration)
- Add NotificationSettings modal for user preferences
- Add mention badges on room list cards
- Add ReportPreview with Markdown rendering and copy/download
- Add message copy functionality with hover actions
- Add backend mentions field to messages with Alembic migration
- Add lots field to rooms, remove templates
- Optimize WebSocket database session handling
- Various UX polish (animations, accessibility)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/modules/chat_room/models.py

@@ -3,11 +3,10 @@
 Tables:
 - tr_incident_rooms: Stores room metadata and configuration
 - tr_room_members: User-room associations with roles
-- tr_room_templates: Predefined templates for common incident types
 
 Note: All tables use 'tr_' prefix to avoid conflicts in shared database.
 """
-from sqlalchemy import Column, Integer, String, Text, DateTime, Enum, ForeignKey, UniqueConstraint, Index
+from sqlalchemy import Column, Integer, String, Text, DateTime, Enum, ForeignKey, UniqueConstraint, Index, JSON
 from sqlalchemy.orm import relationship
 from datetime import datetime
 import enum
@@ -58,6 +57,7 @@ class IncidentRoom(Base):
     location = Column(String(255))
     description = Column(Text)
     resolution_notes = Column(Text)
+    lots = Column(JSON, default=list, nullable=False, comment="LOT batch numbers (JSON array)")
 
     # User tracking
     created_by = Column(String(255), nullable=False)  # User email/ID who created the room
@@ -111,18 +111,4 @@ class RoomMember(Base):
         UniqueConstraint("room_id", "user_id", "removed_at", name="uq_tr_room_member_active"),
         Index("ix_tr_room_members_room_user", "room_id", "user_id"),
         Index("ix_tr_room_members_user", "user_id"),
-    )
-
-
-class RoomTemplate(Base):
-    """Predefined templates for common incident types"""
-
-    __tablename__ = "tr_room_templates"
-
-    template_id = Column(Integer, primary_key=True, autoincrement=True)
-    name = Column(String(100), unique=True, nullable=False)
-    description = Column(Text)
-    incident_type = Column(Enum(IncidentType), nullable=False)
-    default_severity = Column(Enum(SeverityLevel), nullable=False)
-    default_members = Column(Text)  # JSON array of user roles
-    metadata_fields = Column(Text)  # JSON schema for additional fields
+    )