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/session_list.html

@@ -1,4 +1,4 @@
-<!-- Recording Sessions List -->
+<!-- Monitoring Sessions List -->
 {% if sessions %}
     <div class="space-y-4">
         {% for item in sessions %}
@@ -87,7 +87,7 @@
         <svg class="w-16 h-16 mx-auto mb-4 text-gray-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
             <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 19V6l12-3v13M9 19c0 1.105-1.343 2-3 2s-3-.895-3-2 1.343-2 3-2 3 .895 3 2zm12-3c0 1.105-1.343 2-3 2s-3-.895-3-2 1.343-2 3-2 3 .895 3 2zM9 10l12-3"></path>
         </svg>
-        <p class="text-gray-500 dark:text-gray-400 mb-2">No recording sessions yet</p>
+        <p class="text-gray-500 dark:text-gray-400 mb-2">No monitoring sessions yet</p>
         <p class="text-sm text-gray-400 dark:text-gray-500">Schedule a session to get started</p>
     </div>
 {% endif %}
@@ -99,7 +99,7 @@ function viewSession(sessionId) {
 }
 
 function stopRecording(sessionId) {
-    if (!confirm('Stop this recording session?')) return;
+    if (!confirm('Stop this monitoring session?')) return;
 
     // TODO: Implement stop recording API call
     alert('Stop recording API coming soon for session: ' + sessionId);