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>

backend/models.py

@@ -245,17 +245,17 @@ class ScheduledAction(Base):
     created_at = Column(DateTime, default=datetime.utcnow)
 
 
-class RecordingSession(Base):
+class MonitoringSession(Base):
     """
-    Recording sessions: tracks actual monitoring sessions.
-    Created when recording starts, updated when it stops.
+    Monitoring sessions: tracks actual monitoring sessions.
+    Created when monitoring starts, updated when it stops.
     """
-    __tablename__ = "recording_sessions"
+    __tablename__ = "monitoring_sessions"
 
     id = Column(String, primary_key=True, index=True)  # UUID
     project_id = Column(String, nullable=False, index=True)  # FK to Project.id
     location_id = Column(String, nullable=False, index=True)  # FK to MonitoringLocation.id
-    unit_id = Column(String, nullable=False, index=True)  # FK to RosterUnit.id
+    unit_id = Column(String, nullable=True, index=True)  # FK to RosterUnit.id (nullable for offline uploads)
 
     session_type = Column(String, nullable=False)  # sound | vibration
     started_at = Column(DateTime, nullable=False)
@@ -278,7 +278,7 @@ class DataFile(Base):
     __tablename__ = "data_files"
 
     id = Column(String, primary_key=True, index=True)  # UUID
-    session_id = Column(String, nullable=False, index=True)  # FK to RecordingSession.id
+    session_id = Column(String, nullable=False, index=True)  # FK to MonitoringSession.id
 
     file_path = Column(String, nullable=False)  # Relative to data/Projects/
     file_type = Column(String, nullable=False)  # wav, csv, mseed, json