Add WebSocket, multi API key, geocoding proxy, beacon map picker, and comprehensive bug fixes

- Multi API Key + permission system (read/write/admin) with SHA-256 hash
- WebSocket real-time push (location, alarm, device_status, attendance, bluetooth)
- Geocoding proxy endpoints for Amap POI search and reverse geocode
- Beacon modal map-based location picker with search and click-to-select
- GCJ-02 ↔ WGS-84 bidirectional coordinate conversion
- Data cleanup scheduler (configurable retention days)
- Fix GPS longitude sign inversion (course_status bit 11: 0=East, 1=West)
- Fix 2G CellID 2→3 bytes across all protocols (0x28, 0x2C, parser.py)
- Fix parser loop guards, alarm_source field length, CommandLog.sent_at
- Fix geocoding IMEI parameterization, require_admin import
- Improve API error messages for 422 validation errors
- Remove beacon floor/area fields (consolidated into name)

via [HAPI](https://hapi.run)

Co-Authored-By: HAPI <noreply@hapi.run>

app/models.py

@@ -129,7 +129,7 @@ class AlarmRecord(Base):
         String(30), nullable=False
     )  # sos, low_battery, power_on, power_off, enter_fence, exit_fence, ...
     alarm_source: Mapped[str | None] = mapped_column(
-        String(10), nullable=True
+        String(20), nullable=True
     )  # single_fence, multi_fence, lbs, wifi
     protocol_number: Mapped[int] = mapped_column(Integer, nullable=False)
     latitude: Mapped[float | None] = mapped_column(Float, nullable=True)
@@ -321,3 +321,22 @@ class CommandLog(Base):
             f"<CommandLog(id={self.id}, device_id={self.device_id}, "
             f"type={self.command_type}, status={self.status})>"
         )
+
+
+class ApiKey(Base):
+    """API keys for external system authentication."""
+
+    __tablename__ = "api_keys"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    key_hash: Mapped[str] = mapped_column(String(64), unique=True, index=True, nullable=False)
+    name: Mapped[str] = mapped_column(String(100), nullable=False)
+    permissions: Mapped[str] = mapped_column(
+        String(20), default="read", nullable=False
+    )  # read, write, admin
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    last_used_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=_utcnow, nullable=False)
+
+    def __repr__(self) -> str:
+        return f"<ApiKey(id={self.id}, name={self.name}, permissions={self.permissions})>"