feat: add manual SD card data upload for offline NRLs; rename RecordingSession to MonitoringSession

- Add POST /api/projects/{project_id}/nrl/{location_id}/upload-data endpoint
  accepting a ZIP or multi-file select of .rnd/.rnh files from an SD card.
  Parses .rnh metadata for session start/stop times, serial number, and store
  name. Creates a MonitoringSession (no unit assignment required) and DataFile
  records for each measurement file.

- Add Upload Data button and collapsible upload panel to the NRL detail Data
  Files tab, with inline success/error feedback and automatic file list refresh
  via HTMX after import.

- Rename RecordingSession -> MonitoringSession throughout the codebase
  (models.py, projects.py, project_locations.py, scheduler.py, roster_rename.py,
  main.py, init_projects_db.py, scripts/rename_unit.py). DB table renamed from
  recording_sessions to monitoring_sessions; old indexes dropped and recreated.

- Update all template UI copy from Recording Sessions to Monitoring Sessions
  (nrl_detail, projects/detail, session_list, schedule_oneoff, roster).

- Add backend/migrate_rename_recording_to_monitoring_sessions.py for applying
  the table rename on production databases before deploying this build.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

templates/partials/projects/schedule_oneoff.html

@@ -5,7 +5,7 @@
     <div class="mb-4">
         <h4 class="text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">One-Off Recording</h4>
         <p class="text-xs text-gray-500 dark:text-gray-400">
-            Schedule a single recording session with a specific start and end time.
+            Schedule a single monitoring session with a specific start and end time.
             Duration can be between 15 minutes and 24 hours.
         </p>
     </div>