feat(web): UI carica/stacca ricetta + match con ricetta caricata

Manca il path "load" della V feature: utente poteva salvare ricetta
ma non caricarla dalla UI. Aggiunto:

Server:
- POST /recipes/{name}/load: carica .npz in cache _RECIPE_MATCHERS
- POST /match_recipe: usa matcher caricato senza re-train (zero
  training time, solo find params propagati)

UI:
- Dropdown ricette disponibili (auto-refreshed da GET /recipes)
- Bottone "Carica" attiva ricetta + popola state.active_recipe
- Bottone "Stacca" torna al flow normale (training da ROI)
- Status indicator mostra ricetta attiva e dimensioni

doMatch dispatcha automaticamente:
- ricetta attiva → /match_recipe (no model/ROI necessari)
- altrimenti → /match o /match_simple come prima

Use case: ricetta tarata offline, deploy a runtime production senza
ricaricare modello+ROI ogni volta.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pm2d/web/server.py

@@ -676,6 +676,102 @@ def list_recipes():
     return {"files": files, "dir": str(RECIPES_DIR)}
 
 
+# Cache di matcher caricati da .npz (V feature). Key: nome ricetta.
+_RECIPE_MATCHERS: OrderedDict = OrderedDict()
+_RECIPE_MATCHERS_SIZE = 4
+
+
+@app.post("/recipes/{name}/load")
+def load_recipe(name: str):
+    """Carica ricetta .npz e popola cache matcher in memoria.
+
+    Una volta caricata, /match_recipe la usa direttamente senza
+    re-train. Halcon-equivalent read_shape_model + handle.
+    """
+    safe_name = "".join(c for c in name if c.isalnum() or c in "._-")
+    if not safe_name.endswith(".npz"):
+        safe_name += ".npz"
+    path = RECIPES_DIR / safe_name
+    if not path.is_file():
+        raise HTTPException(404, f"Ricetta non trovata: {safe_name}")
+    m = LineShapeMatcher.load_model(str(path))
+    _RECIPE_MATCHERS[safe_name] = m
+    _RECIPE_MATCHERS.move_to_end(safe_name)
+    while len(_RECIPE_MATCHERS) > _RECIPE_MATCHERS_SIZE:
+        _RECIPE_MATCHERS.popitem(last=False)
+    return {
+        "name": safe_name,
+        "n_variants": len(m.variants),
+        "template_size": list(m.template_size),
+        "use_polarity": m.use_polarity,
+    }
+
+
+class RecipeMatchParams(BaseModel):
+    recipe: str
+    scene_id: str
+    # Solo find-time params (training gia' fatto offline)
+    min_score: float = 0.65
+    max_matches: int = 25
+    min_recall: float = 0.0
+    use_soft_score: bool = False
+    subpixel_lm: bool = False
+    nms_iou_threshold: float = 0.3
+    coarse_stride: int = 1
+    pyramid_propagate: bool = False
+    greediness: float = 0.0
+    refine_pose_joint: bool = False
+    search_roi: list[int] | None = None
+    verify_threshold: float = 0.5
+    scale_penalty: float = 0.0
+
+
+@app.post("/match_recipe", response_model=MatchResp)
+def match_recipe(p: RecipeMatchParams):
+    """Match con ricetta pre-trained: zero training, solo find."""
+    safe_name = p.recipe if p.recipe.endswith(".npz") else f"{p.recipe}.npz"
+    m = _RECIPE_MATCHERS.get(safe_name)
+    if m is None:
+        # Auto-load on demand
+        path = RECIPES_DIR / safe_name
+        if not path.is_file():
+            raise HTTPException(404, f"Ricetta non trovata: {safe_name}")
+        m = LineShapeMatcher.load_model(str(path))
+        _RECIPE_MATCHERS[safe_name] = m
+    scene = _load_image(p.scene_id)
+    if scene is None:
+        raise HTTPException(404, "Scena non trovata")
+    search_roi_t = tuple(p.search_roi) if p.search_roi else None
+    t0 = time.time()
+    matches = m.find(
+        scene,
+        min_score=p.min_score, max_matches=p.max_matches,
+        verify_threshold=p.verify_threshold,
+        scale_penalty=p.scale_penalty,
+        min_recall=p.min_recall,
+        use_soft_score=p.use_soft_score,
+        subpixel_lm=p.subpixel_lm,
+        nms_iou_threshold=p.nms_iou_threshold,
+        coarse_stride=p.coarse_stride,
+        pyramid_propagate=p.pyramid_propagate,
+        greediness=p.greediness,
+        refine_pose_joint=p.refine_pose_joint,
+        search_roi=search_roi_t,
+    )
+    t_find = time.time() - t0
+    tg = m.template_gray if m.template_gray is not None else np.zeros((1, 1), np.uint8)
+    annotated = _draw_matches(scene, matches, tg)
+    ann_id = _store_image(annotated)
+    return MatchResp(
+        matches=[MatchResult(
+            cx=mt.cx, cy=mt.cy, angle_deg=mt.angle_deg, scale=mt.scale,
+            score=mt.score, bbox_poly=mt.bbox_poly.tolist(),
+        ) for mt in matches],
+        train_time=0.0, find_time=t_find,
+        num_variants=len(m.variants), annotated_id=ann_id,
+    )
+
+
 # Mount static
 app.mount("/static", StaticFiles(directory=STATIC_DIR), name="static")