feat(devices): add ResetStatsRequest/ResetStatsResult models

Missed from the previous Reset Stats commit — these are the
request/response schemas for POST /devices/{id}/reset-stats.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/devices/models.py

@@ -226,3 +226,39 @@ class DeviceUserInfo(BaseModel):
 class DeviceUsersResponse(BaseModel):
     users: List[DeviceUserInfo]
     total: int
+
+
+class ResetStatsRequest(BaseModel):
+    """Which categories of QA/bench test data to clear before shipping a
+    device to a customer. Each flag is independent — callers check only the
+    boxes they want. device_stats (Firestore) and current_alerts both default
+    to False since they need extra care (current_alerts especially — see
+    ResetStatsResult.current_alerts note)."""
+    bell_stats: bool = False           # Firestore device_stats: totalHammerStrikes, perBellStrikes
+    playback_stats: bool = False       # Firestore device_stats: totalPlaybacks, totalWarningsGiven
+    device_logs: bool = False          # Postgres device_logs
+    heartbeats: bool = False           # Postgres heartbeats
+    commands: bool = False             # Postgres commands
+    boot_events: bool = False          # Postgres device_boot_events (console-side history)
+    alert_history: bool = False        # Postgres device_alert_events
+    ping_samples: bool = False         # Postgres device_ping_samples
+    diagnostics_reports: bool = False  # Postgres device_diagnostics_reports
+    reports: bool = False              # Postgres device_reports (control/reports history, e.g. bell_overload)
+    current_alerts: bool = False       # Postgres device_alerts (LIVE state — opt-in only)
+
+
+class ResetStatsResult(BaseModel):
+    """Per-category outcome. Postgres/Firestore categories always run
+    (device connectivity doesn't matter); counts are rows deleted, or null
+    for categories that weren't requested."""
+    bell_stats: Optional[bool] = None
+    playback_stats: Optional[bool] = None
+    device_logs: Optional[int] = None
+    heartbeats: Optional[int] = None
+    commands: Optional[int] = None
+    boot_events: Optional[int] = None
+    alert_history: Optional[int] = None
+    ping_samples: Optional[int] = None
+    diagnostics_reports: Optional[int] = None
+    reports: Optional[int] = None
+    current_alerts: Optional[int] = None