Remove obsolete slicer_binary_path setting from database

  The slicer_binary_path key was left in the settings table from earlier
  slicer integration research but is no longer referenced anywhere in the
  codebase. Add a startup migration step that deletes orphaned settings
  keys so they don't persist in backups.

CHANGELOG.md

@@ -52,6 +52,7 @@ All notable changes to Bambuddy will be documented in this file.
 - **Filament ID Conversion Utility** — Extracted filament_id ↔ setting_id conversion logic into a shared utility (`backend/app/utils/filament_ids.py`). The `assign_spool` endpoint now normalizes `slicer_filament` (which can be stored in either filament_id format like "GFL05" or setting_id format like "GFSL05_07") into the correct `tray_info_idx` and `setting_id` for the MQTT command. Previously `setting_id` was always sent as empty string, which could cause BambuStudio to not resolve the filament preset for the AMS slot.
 - **Updates Card Separates Firmware and Software Settings** — The Updates card on the Settings page mixed printer firmware and Bambuddy software update toggles with no visual grouping. Now splits the card into two labeled sections ("Printer Firmware" and "Bambuddy Software") separated by a divider, making it clear which toggles control what.
 - **SpoolBuddy Test Coverage** — Added integration tests for all 12 SpoolBuddy API endpoints (21 backend tests covering device registration/re-registration, heartbeat status and pending commands, NFC tag scan/match/removal, scale reading broadcast, spool weight calculation, and scale calibration including tare, set-factor, and zero-delta error handling) and component tests for the three main SpoolBuddy frontend components (20 frontend tests covering WeightDisplay weight formatting and status indicators, SpoolInfoCard spool info rendering and action callbacks, UnknownTagCard tag display, and TagDetectedModal open/close/escape behavior with known and unknown spool views).
+- **Cleanup Obsolete Settings** — The startup migration now deletes orphaned settings keys from the database that are no longer used by the application (e.g., `slicer_binary_path` from earlier slicer integration research).
 
 ## [0.2.1] - 2026-02-27
 

backend/app/core/database.py

@@ -1360,6 +1360,11 @@ async def run_migrations(conn):
     except OperationalError:
         pass  # Already applied
 
+    # Cleanup: Remove obsolete settings keys that are no longer used
+    obsolete_keys = ["slicer_binary_path"]
+    for key in obsolete_keys:
+        await conn.execute(text("DELETE FROM settings WHERE key = :key"), {"key": key})
+
 
 async def seed_notification_templates():
     """Seed default notification templates if they don't exist."""