fix(trt): drop explicit shapes for static TransNetV2; gallery over-fetch + dedup

trtexec rejects --minShapes/--optShapes/--maxShapes for a fully static model
("Static model does not take explicit shapes"). TransNetV2's input is fixed at
1x100x27x48x3, so the shape comes from the model itself.

Gallery build now over-fetches TMDB/Wikidata candidates by a configurable
factor: near-duplicate stills (the same photo at different crops or
resolutions) are discarded after embedding, so downloading exactly
images_per_actor left actors short of that many *distinct* embeddings.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/face_embedder_engine.hpp

@@ -32,16 +32,23 @@ struct FaceEmbedResult {
 
 class FaceEmbedderEngine {
 public:
+    // detector_engine/arcface_engine are optional paths to pre-built TensorRT
+    // engines. They are required when built with SAE_INFERENCE_BACKEND=TRT
+    // (which cannot load .onnx directly) and ignored by the ORT backend.
     FaceEmbedderEngine(const std::string& detector_model,
                         const std::string& arcface_model,
-                        float conf = 0.5f, float nms = 0.4f, int max_side = 500)
+                        float conf = 0.5f, float nms = 0.4f, int max_side = 500,
+                        const std::string& detector_engine = "",
+                        const std::string& arcface_engine = "")
         : max_side_(max_side)
     {
         Config cfg;
-        cfg.detector_model = detector_model;
-        cfg.arcface_model  = arcface_model;
-        cfg.detector_conf  = conf;
-        cfg.detector_nms   = nms;
+        cfg.detector_model  = detector_model;
+        cfg.arcface_model   = arcface_model;
+        cfg.detector_engine = detector_engine;
+        cfg.arcface_engine  = arcface_engine;
+        cfg.detector_conf   = conf;
+        cfg.detector_nms    = nms;
         detector_ = make_face_detector(cfg);
         embedder_ = make_face_embedder(cfg);
     }