feat(suggestions): tag-input dropdown searches the full prediction set

The typed dropdown sourced the threshold-filtered panel list (>= 0.70 general),
so low-confidence actions/features the model DID predict never appeared — forcing
hand-typed custom tags instead of accepting the model's canonical formatting.

Add a threshold override: SuggestionService.for_image(threshold_override=) and
GET /images/<id>/suggestions?min=<f> surface EVERY stored prediction (down to the
0.05 store floor), alias-resolved and normalized, still excluding applied/rejected
and unsurfaced categories. The suggestions store gains allByCategory + loadAll
(min=0); the dropdown searches that full set (cap 20), while the Suggestions panel
stays curated at the configured threshold. Accept/dismiss drop from both lists.

Operator-asked 2026-06-09. Test: a 0.30 general prediction is hidden by default
but surfaced with threshold_override=0.0; unsurfaced categories still excluded.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/app/api/suggestions.py

@@ -11,8 +11,21 @@ suggestions_bp = Blueprint("suggestions", __name__, url_prefix="/api")
 
 @suggestions_bp.route("/images/<int:image_id>/suggestions", methods=["GET"])
 async def get_suggestions(image_id: int):
+    # ?min=<float> overrides the configured per-category thresholds so the typed
+    # tag-input dropdown can surface EVERY stored prediction (min=0), including
+    # low-confidence actions/features, in canonical formatting. Omitted → the
+    # curated above-threshold list the Suggestions panel uses.
+    override = None
+    raw_min = request.args.get("min")
+    if raw_min is not None:
+        try:
+            override = min(1.0, max(0.0, float(raw_min)))
+        except ValueError:
+            return jsonify({"error": "min must be a float in [0,1]"}), 400
     async with get_session() as session:
-        sl = await SuggestionService(session).for_image(image_id)
+        sl = await SuggestionService(session).for_image(
+            image_id, threshold_override=override
+        )
     return jsonify(
         {
             "by_category": {