feat(trackers): user filters for Gitea, webhook polling cleanup, dashboard navigability

- Gitea: NotificationTracker now exposes sender allowlist / blocklist filters
  via MultiEntitySelect, populated from Gitea /users/search merged with past
  EventLog senders so the picker is useful before the first webhook arrives.
- Webhook providers (gitea, planka, webhook): stop scheduling interval polling
  jobs on tracker create/update/startup; hide the "every Xs" indicator in the
  tracker list since there is no polling.
- Dashboard: stat cards are now <a> links that route to providers, trackers,
  targets, command-trackers, or scroll to the events panel. Provider deck
  rows highlight the target provider on click.
- Command trackers / command configs: auto-reselect the right config when the
  provider type changes (matches notification-tracker behavior).
- Migration: drop legacy batch_duration column from notification_tracker —
  the field is gone from the model but its NOT NULL constraint blocked
  inserts on older DBs.
- Docs: refresh entity-relationships.md with current NotificationTracker
  fields (filters, adaptive_max_skip, default_*_config_id).

packages/core/src/notify_bridge_core/providers/gitea/client.py

@@ -150,6 +150,40 @@ class GiteaClient:
             _LOGGER.warning("Failed to fetch commits for %s/%s: %s", owner, repo, err)
         return []
 
+    async def get_users(self, limit: int = 200) -> list[dict[str, Any]]:
+        """List users known to the Gitea instance via /users/search.
+
+        ``/users/search`` with an empty ``q`` returns all users the
+        authenticated token can see, paginated. We cap at ``limit`` to avoid
+        unbounded memory on large instances; the picker only needs enough to
+        cover senders that may appear in webhook payloads.
+        """
+        users: list[dict[str, Any]] = []
+        page = 1
+        per_page = min(50, limit)
+        while len(users) < limit:
+            try:
+                async with self._session.get(
+                    f"{self._url}/api/v1/users/search",
+                    headers=self._headers,
+                    params={"page": str(page), "limit": str(per_page)},
+                ) as response:
+                    if response.status != 200:
+                        _LOGGER.warning("Failed to fetch users: HTTP %s", response.status)
+                        break
+                    body = await response.json()
+                    items = body.get("data", []) if isinstance(body, dict) else body
+                    if not items:
+                        break
+                    users.extend(items)
+                    if len(items) < per_page:
+                        break
+                    page += 1
+            except aiohttp.ClientError as err:
+                _LOGGER.warning("Failed to fetch users: %s", err)
+                break
+        return users[:limit]
+
 
 class GiteaApiError(Exception):
     """Raised when a Gitea API call fails."""