feat: Add support for Frigate reviews / detections [initial PR] (#2315)

- Add support for Frigate reviews / detections.
 - Add support for GenAI metadata.
- Significant internal refactor to more flexible "UnifiedQuery" to allow
mixing cameras with simple metadata and review metadata (e.g. a timeline
view of a Frigate camera with reviews, and a Reolink camera with simple
metadata).
 - Add support for folder media as camera media.

There are a few more PRs to commit prior to this going live, but
commiting this for now due to the scale of the change.

BREAKING CHANGE: `media_type` and `events_type` are retired under
`live`, `viewer` and `timeline` configuration sections, instead media
type is associated (once) with the camera under `media`.

src/query-source.ts

@@ -0,0 +1,52 @@
+export enum QuerySource {
+  // Camera queries are handled by CameraManager.
+  Camera = 'camera',
+
+  // Folder queries are handled by FolderManager.
+  Folder = 'folder',
+}
+
+export interface BaseQuery {
+  source: QuerySource;
+}
+
+/**
+ * Filter properties that can be applied to queries.
+ * Not all query types support all filters -- engines reject unsupported ones.
+ */
+export interface QueryFilters {
+  favorite?: boolean;
+  tags?: Set<string>;
+  what?: Set<string>;
+  where?: Set<string>;
+  reviewed?: boolean;
+}
+
+/**
+ * Declares which filters a query handler supports.
+ * Used by hasUnsupportedFilters() to check compatibility.
+ */
+interface SupportedFilters {
+  favorite?: boolean;
+  tags?: boolean;
+  what?: boolean;
+  where?: boolean;
+  reviewed?: boolean;
+}
+
+/**
+ * Check if a query has filters that aren't supported.
+ * Returns true if the query has any filter that isn't in the supported set.
+ */
+export const hasUnsupportedFilters = (
+  query: QueryFilters,
+  supported: SupportedFilters = {},
+): boolean => {
+  return (
+    (!supported.favorite && query.favorite !== undefined) ||
+    (!supported.tags && !!query.tags?.size) ||
+    (!supported.what && !!query.what?.size) ||
+    (!supported.where && !!query.where?.size) ||
+    (!supported.reviewed && query.reviewed !== undefined)
+  );
+};