Semantic Search Triggers (#18969)

* semantic trigger test

* database and model

* config

* embeddings maintainer and trigger post-processor

* api to create, edit, delete triggers

* frontend and i18n keys

* use thumbnail and description for trigger types

* image picker tweaks

* initial sync

* thumbnail file management

* clean up logs and use saved thumbnail on frontend

* publish mqtt messages

* webpush changes to enable trigger notifications

* add enabled switch

* add triggers from explore

* renaming and deletion fixes

* fix typing

* UI updates and add last triggering event time and link

* log exception instead of return in endpoint

* highlight entry in UI when triggered

* save and delete thumbnails directly

* remove alert action for now and add descriptions

* tweaks

* clean up

* fix types

* docs

* docs tweaks

* docs

* reuse enum

frigate/util/builtin.py

@@ -428,3 +428,19 @@ def sanitize_float(value):
     if isinstance(value, (int, float)) and not math.isfinite(value):
         return 0.0
     return value
+
+
+def cosine_similarity(a: np.ndarray, b: np.ndarray) -> float:
+    return 1 - cosine_distance(a, b)
+
+
+def cosine_distance(a: np.ndarray, b: np.ndarray) -> float:
+    """Returns cosine distance to match sqlite-vec's calculation."""
+    dot = np.dot(a, b)
+    a_mag = np.dot(a, a)  # ||a||^2
+    b_mag = np.dot(b, b)  # ||b||^2
+
+    if a_mag == 0 or b_mag == 0:
+        return 1.0
+
+    return 1.0 - (dot / (np.sqrt(a_mag) * np.sqrt(b_mag)))