Fix TSCM sweep scan resilience and add per-device error isolation

The sweep loop's WiFi/BT/RF scan processing had unprotected
timeline_manager.add_observation() calls that could crash an entire
scan iteration, silently preventing all device events from reaching
the frontend. Additionally, scan interval timestamps were only updated
at the end of processing, causing tight retry loops on persistent errors.

- Wrap timeline observation calls in try/except for all three protocols
- Move last_*_scan timestamp updates immediately after scan completes
- Add per-device try/except so one bad device doesn't block others
- Emit sweep_progress after WiFi scan for real-time status visibility
- Log warning when WiFi scan returns 0 networks for easier diagnosis
- Add known_device and score_modifier fields to correlation engine
- Add TSCM scheduling, cases, known devices, and advanced WiFi indicators

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

utils/database.py

@@ -1205,21 +1205,127 @@ def get_all_known_devices(
         ]
 
 
-def delete_known_device(identifier: str) -> bool:
-    """Remove a device from the known-good registry."""
-    with get_db() as conn:
-        cursor = conn.execute(
-            'DELETE FROM tscm_known_devices WHERE identifier = ?',
-            (identifier.upper(),)
-        )
-        return cursor.rowcount > 0
-
-
-def is_known_good_device(identifier: str, location: str | None = None) -> dict | None:
-    """Check if a device is in the known-good registry for a location."""
-    with get_db() as conn:
-        if location:
-            cursor = conn.execute('''
+def delete_known_device(identifier: str) -> bool:
+    """Remove a device from the known-good registry."""
+    with get_db() as conn:
+        cursor = conn.execute(
+            'DELETE FROM tscm_known_devices WHERE identifier = ?',
+            (identifier.upper(),)
+        )
+        return cursor.rowcount > 0
+
+
+# =============================================================================
+# TSCM Schedule Functions
+# =============================================================================
+
+def create_tscm_schedule(
+    name: str,
+    cron_expression: str,
+    sweep_type: str = 'standard',
+    baseline_id: int | None = None,
+    zone_name: str | None = None,
+    enabled: bool = True,
+    notify_on_threat: bool = True,
+    notify_email: str | None = None,
+    last_run: str | None = None,
+    next_run: str | None = None,
+) -> int:
+    """Create a new TSCM sweep schedule."""
+    with get_db() as conn:
+        cursor = conn.execute('''
+            INSERT INTO tscm_schedules
+            (name, baseline_id, zone_name, cron_expression, sweep_type,
+             enabled, last_run, next_run, notify_on_threat, notify_email)
+            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+        ''', (
+            name,
+            baseline_id,
+            zone_name,
+            cron_expression,
+            sweep_type,
+            1 if enabled else 0,
+            last_run,
+            next_run,
+            1 if notify_on_threat else 0,
+            notify_email,
+        ))
+        return cursor.lastrowid
+
+
+def get_tscm_schedule(schedule_id: int) -> dict | None:
+    """Get a TSCM schedule by ID."""
+    with get_db() as conn:
+        cursor = conn.execute(
+            'SELECT * FROM tscm_schedules WHERE id = ?',
+            (schedule_id,)
+        )
+        row = cursor.fetchone()
+        return dict(row) if row else None
+
+
+def get_all_tscm_schedules(
+    enabled: bool | None = None,
+    limit: int = 200
+) -> list[dict]:
+    """Get all TSCM schedules."""
+    conditions = []
+    params = []
+
+    if enabled is not None:
+        conditions.append('enabled = ?')
+        params.append(1 if enabled else 0)
+
+    where_clause = f'WHERE {" AND ".join(conditions)}' if conditions else ''
+    params.append(limit)
+
+    with get_db() as conn:
+        cursor = conn.execute(f'''
+            SELECT * FROM tscm_schedules
+            {where_clause}
+            ORDER BY id DESC
+            LIMIT ?
+        ''', params)
+        return [dict(row) for row in cursor]
+
+
+def update_tscm_schedule(schedule_id: int, **fields) -> bool:
+    """Update a TSCM schedule."""
+    if not fields:
+        return False
+
+    updates = []
+    params = []
+
+    for key, value in fields.items():
+        updates.append(f'{key} = ?')
+        params.append(value)
+
+    params.append(schedule_id)
+
+    with get_db() as conn:
+        cursor = conn.execute(
+            f'UPDATE tscm_schedules SET {", ".join(updates)} WHERE id = ?',
+            params
+        )
+        return cursor.rowcount > 0
+
+
+def delete_tscm_schedule(schedule_id: int) -> bool:
+    """Delete a TSCM schedule."""
+    with get_db() as conn:
+        cursor = conn.execute(
+            'DELETE FROM tscm_schedules WHERE id = ?',
+            (schedule_id,)
+        )
+        return cursor.rowcount > 0
+
+
+def is_known_good_device(identifier: str, location: str | None = None) -> dict | None:
+    """Check if a device is in the known-good registry for a location."""
+    with get_db() as conn:
+        if location:
+            cursor = conn.execute('''
                 SELECT * FROM tscm_known_devices
                 WHERE identifier = ? AND (location = ? OR scope = 'global')
             ''', (identifier.upper(), location))