fix: critical timestamp parsing and audit fixes

- Fix timestamp conversion: String(epochMs) → new Date(epochMs).toISOString()
  in use-messages-sync, use-comments-sync, use-documents, use-inbox.
  Without this, date comparisons (isEdited, cutoff filters) would fail.
- Fix updated_at: undefined → null in use-inbox to match InboxItem type
- Fix ZeroProvider: skip Zero connection for unauthenticated users
- Clean 30+ stale "Electric SQL" comments in backend Python code

surfsense_backend/app/tasks/celery_tasks/document_tasks.py

@@ -887,7 +887,7 @@ async def _process_file_with_document(
         )
 
         try:
-            # Set status to PROCESSING (shows spinner in UI via ElectricSQL)
+            # Set status to PROCESSING (shows spinner in UI via Zero)
             document.status = DocumentStatus.processing()
             await session.commit()
             logger.info(
@@ -951,7 +951,7 @@ async def _process_file_with_document(
             ):
                 page_limit_error = e.__cause__
 
-            # Mark document as failed (shows error in UI via ElectricSQL)
+            # Mark document as failed (shows error in UI via Zero)
             error_message = str(e)[:500]
             document.status = DocumentStatus.failed(error_message)
             document.updated_at = get_current_timestamp()

surfsense_backend/app/tasks/connector_indexers/airtable_indexer.py

@@ -139,7 +139,7 @@ async def index_airtable_records(
                 await task_logger.log_task_success(
                     log_entry, success_msg, {"bases_count": 0}
                 )
-                # CRITICAL: Update timestamp even when no bases found so Electric SQL syncs
+                # CRITICAL: Update timestamp even when no bases found so Zero syncs
                 await update_connector_last_indexed(
                     session, connector, update_last_indexed
                 )
@@ -460,7 +460,7 @@ async def index_airtable_records(
                     documents_failed += 1
                     continue
 
-            # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+            # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
             await update_connector_last_indexed(session, connector, update_last_indexed)
 
             total_processed = documents_indexed

surfsense_backend/app/tasks/connector_indexers/bookstack_indexer.py

@@ -462,7 +462,7 @@ async def index_bookstack_pages(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         # This ensures the UI shows "Last indexed" instead of "Never indexed"
         await update_connector_last_indexed(session, connector, update_last_indexed)
 

surfsense_backend/app/tasks/connector_indexers/clickup_indexer.py

@@ -470,7 +470,7 @@ async def index_clickup_tasks(
 
         total_processed = documents_indexed
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         # This ensures the UI shows "Last indexed" instead of "Never indexed"
         await update_connector_last_indexed(session, connector, update_last_indexed)
 

surfsense_backend/app/tasks/connector_indexers/confluence_indexer.py

@@ -442,7 +442,7 @@ async def index_confluence_pages(
                 documents_failed += 1
                 continue  # Skip this page and continue with others
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         # This ensures the UI shows "Last indexed" instead of "Never indexed"
         await update_connector_last_indexed(session, connector, update_last_indexed)
 

surfsense_backend/app/tasks/connector_indexers/discord_indexer.py

@@ -718,7 +718,7 @@ async def index_discord_messages(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/elasticsearch_indexer.py

@@ -413,7 +413,7 @@ async def index_elasticsearch_documents(
                     documents_failed += 1
                     continue
 
-            # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+            # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
             # This ensures the UI shows "Last indexed" instead of "Never indexed"
             if update_last_indexed:
                 connector.last_indexed_at = (

surfsense_backend/app/tasks/connector_indexers/github_indexer.py

@@ -451,7 +451,7 @@ async def index_github_repos(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit

surfsense_backend/app/tasks/connector_indexers/google_calendar_indexer.py

@@ -554,7 +554,7 @@ async def index_google_calendar_events(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/google_gmail_indexer.py

@@ -477,7 +477,7 @@ async def index_google_gmail_messages(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/jira_indexer.py

@@ -422,7 +422,7 @@ async def index_jira_issues(
                 documents_failed += 1
                 continue  # Skip this issue and continue with others
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         # This ensures the UI shows "Last indexed" instead of "Never indexed"
         await update_connector_last_indexed(session, connector, update_last_indexed)
 

surfsense_backend/app/tasks/connector_indexers/linear_indexer.py

@@ -463,7 +463,7 @@ async def index_linear_issues(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/luma_indexer.py

@@ -520,7 +520,7 @@ async def index_luma_events(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         # This ensures the UI shows "Last indexed" instead of "Never indexed"
         await update_connector_last_indexed(session, connector, update_last_indexed)
 

surfsense_backend/app/tasks/connector_indexers/notion_indexer.py

@@ -252,7 +252,7 @@ async def index_notion_pages(
                 {"pages_found": 0},
             )
             logger.info("No Notion pages found to index")
-            # CRITICAL: Update timestamp even when no pages found so Electric SQL syncs
+            # CRITICAL: Update timestamp even when no pages found so Zero syncs
             await update_connector_last_indexed(session, connector, update_last_indexed)
             await session.commit()
             await notion_client.close()
@@ -506,7 +506,7 @@ async def index_notion_pages(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         total_processed = documents_indexed

surfsense_backend/app/tasks/connector_indexers/obsidian_indexer.py

@@ -599,7 +599,7 @@ async def index_obsidian_vault(
                 failed_count += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/slack_indexer.py

@@ -256,7 +256,7 @@ async def index_slack_messages(
                 f"No Slack channels found for connector {connector_id}",
                 {"channels_found": 0},
             )
-            # CRITICAL: Update timestamp even when no channels found so Electric SQL syncs
+            # CRITICAL: Update timestamp even when no channels found so Zero syncs
             await update_connector_last_indexed(session, connector, update_last_indexed)
             await session.commit()
             return 0, None  # Return None (not error) when no channels found
@@ -593,7 +593,7 @@ async def index_slack_messages(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/teams_indexer.py

@@ -249,7 +249,7 @@ async def index_teams_messages(
                 f"No Teams found for connector {connector_id}",
                 {"teams_found": 0},
             )
-            # CRITICAL: Update timestamp even when no teams found so Electric SQL syncs
+            # CRITICAL: Update timestamp even when no teams found so Zero syncs
             await update_connector_last_indexed(session, connector, update_last_indexed)
             await session.commit()
             return 0, None  # Return None (not error) when no items found
@@ -635,7 +635,7 @@ async def index_teams_messages(
                 documents_failed += 1
                 continue
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches

surfsense_backend/app/tasks/connector_indexers/webcrawler_indexer.py

@@ -444,7 +444,7 @@ async def index_crawled_urls(
 
         total_processed = documents_indexed + documents_updated
 
-        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Electric SQL syncs
+        # CRITICAL: Always update timestamp (even if 0 documents indexed) so Zero syncs
         await update_connector_last_indexed(session, connector, update_last_indexed)
 
         # Final commit for any remaining documents not yet committed in batches