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_web/hooks/use-comments-sync.ts

@@ -203,8 +203,8 @@ export function useCommentsSync(threadId: number | null) {
 			parent_id: c.parentId ?? null,
 			author_id: c.authorId ?? null,
 			content: c.content,
-			created_at: String(c.createdAt),
-			updated_at: String(c.updatedAt),
+			created_at: new Date(c.createdAt).toISOString(),
+			updated_at: new Date(c.updatedAt).toISOString(),
 		}));
 
 		updateReactQueryCache(rows);

surfsense_web/hooks/use-documents.ts

@@ -242,7 +242,7 @@ export function useDocuments(
 					created_by_email: doc.createdById
 						? (emailCacheRef.current.get(doc.createdById) ?? null)
 						: null,
-					created_at: String(doc.createdAt),
+					created_at: new Date(doc.createdAt).toISOString(),
 					status: (doc.status as unknown as DocumentStatusType) ?? { state: "ready" },
 				}));
 

surfsense_web/hooks/use-inbox.ts

@@ -154,8 +154,8 @@ export function useInbox(
 					message: item.message,
 					read: item.read,
 					metadata: item.metadata as unknown as Record<string, unknown>,
-					created_at: String(item.createdAt),
-					updated_at: item.updatedAt ? String(item.updatedAt) : undefined,
+					created_at: new Date(item.createdAt).toISOString(),
+					updated_at: item.updatedAt ? new Date(item.updatedAt).toISOString() : null,
 				} as InboxItem));
 
 			let updated = prev.map((existing) => {

surfsense_web/hooks/use-messages-sync.ts

@@ -30,7 +30,7 @@ export function useMessagesSync(
 			role: msg.role,
 			content: msg.content,
 			author_id: msg.authorId ?? null,
-			created_at: String(msg.createdAt),
+			created_at: new Date(msg.createdAt).toISOString(),
 		}));
 
 		onMessagesUpdateRef.current(mapped);