feat(ui): Sprint 10 — Deny Forever on Recipes (card overlay + detail button + undo toast)

User-driven follow-up to Sprint 8: surface the Sprint 1-3 NeverSuggest
infrastructure on the Recipes surface so a family can pre-emptively
mark a recipe as never-suggest before it appears in a plan.

Backend (3 changes):
- POST /api/never-suggest (public, webui-facing). Idempotent on
  (family, recipe, reason). Returns the row joined with recipe_name.
- DELETE /api/never-suggest/{ns_id} (public, webui-facing). Row-level
  ownership check (403 if cross-family), 404 if absent.
- NeverSuggestRead.recipe_name + .ingredient_name server-side joins
  via _attach_names() helper (one LEFT OUTER JOIN per kind).
- Admin path (POST/DELETE /api/admin/never-suggest) unchanged.

Frontend (4 changes):
- New NeverSuggestButton component (~290 lines). Two variants: card
  (overlay on RecipeCard) and detail (text buttons in RecipeDetail
  top bar). Popover with Allergy (red, window.confirm) + Dislike
  (neutral, no confirm). Undo toast via showToast.undo() (Sprint 3
  B12 pattern, 6s window). Pre-existing block detection shows a
  Blocked state with an Unblock path.
- mealPlannerApi.neverSuggest.list/add/remove in api/index.ts.
- Recipes.tsx overlay: RecipeCard has position: relative; button is
  opacity-0 group-hover:opacity-100 focus:opacity-100. e.preventDefault
  + e.stopPropagation prevents accidental navigation.
- RecipeDetail.tsx top bar: new Deny forever button group to the left
  of Add to Plan.

Build: npm run build green (tsc 0 errors, vite 0 errors) on
docker-willester. Bundle 487 -> 495 kB. No new dependencies. No
migration (NeverSuggest table exists from prior sprints).

Tracking: Review/sprint10-verification.md (9-step browser smoke +
5 API curls + undo test + a11y check).

backend/app/api/never_suggest.py

@@ -7,9 +7,9 @@ from fastapi import APIRouter, Depends, HTTPException, Query, Response, status
 from sqlalchemy.orm import Session
 
 from app.database import get_db
-from app.models import NeverSuggest, NeverSuggestReason
+from app.models import Ingredient, NeverSuggest, NeverSuggestReason, Recipe
 from app.schemas.never_suggest import NeverSuggestCreate, NeverSuggestRead
-from app.security import require_admin
+from app.security import require_admin, require_session
 
 
 public_router = APIRouter(prefix="/api/never-suggest", tags=["never-suggest"])
@@ -29,16 +29,118 @@ def _coerce_reason(raw: str | None) -> NeverSuggestReason | None:
         raise HTTPException(status_code=422, detail=f"unknown reason: {raw}")
 
 
+def _attach_names(rows: List[NeverSuggest], db: Session) -> List[dict]:
+    """Hydrate recipe_name / ingredient_name for the response.
+
+    One LEFT OUTER JOIN per kind, then merge into the response dicts.
+    A second pass would be a `selectinload` if the list grows; for the
+    family-scale (dozens of rows) this is simpler and fast enough.
+    """
+    recipe_ids = {r.recipe_id for r in rows if r.recipe_id}
+    ingredient_ids = {r.ingredient_id for r in rows if r.ingredient_id}
+    recipe_map: dict[UUID, str] = {}
+    if recipe_ids:
+        for rid, name in db.query(Recipe.id, Recipe.name).filter(Recipe.id.in_(recipe_ids)).all():
+            recipe_map[rid] = name
+    ingredient_map: dict[UUID, str] = {}
+    if ingredient_ids:
+        for iid, name in db.query(Ingredient.id, Ingredient.name).filter(Ingredient.id.in_(ingredient_ids)).all():
+            ingredient_map[iid] = name
+    out = []
+    for r in rows:
+        d = {
+            "id": r.id,
+            "family_profile_id": r.family_profile_id,
+            "ingredient_id": r.ingredient_id,
+            "recipe_id": r.recipe_id,
+            "reason": r.reason.value if r.reason else None,
+            "notes": r.notes,
+            "recipe_name": recipe_map.get(r.recipe_id) if r.recipe_id else None,
+            "ingredient_name": ingredient_map.get(r.ingredient_id) if r.ingredient_id else None,
+        }
+        out.append(d)
+    return out
+
+
 @public_router.get("", response_model=List[NeverSuggestRead])
 def list_for_family(
     family_profile_id: UUID = Query(...),
     db: Session = Depends(get_db),
 ):
-    return (
+    rows = (
         db.query(NeverSuggest)
         .filter(NeverSuggest.family_profile_id == family_profile_id)
         .all()
     )
+    return _attach_names(rows, db)
+
+
+@public_router.post("", response_model=NeverSuggestRead, status_code=status.HTTP_201_CREATED)
+def add_block(
+    payload: NeverSuggestCreate,
+    db: Session = Depends(get_db),
+    _session: str = Depends(require_session),
+):
+    """Family-facing: mark a recipe (or ingredient) as never-suggest.
+
+    Idempotent on (family_profile_id, recipe_id, reason). Re-adding the
+    same row returns the existing row instead of creating a duplicate.
+    The on-conflict check is a single SELECT + INSERT; small enough
+    that we don't need a unique index.
+    """
+    existing = (
+        db.query(NeverSuggest)
+        .filter(
+            NeverSuggest.family_profile_id == payload.family_profile_id,
+            NeverSuggest.recipe_id == payload.recipe_id,
+            NeverSuggest.ingredient_id == payload.ingredient_id,
+            NeverSuggest.reason == _coerce_reason(payload.reason),
+        )
+        .first()
+    )
+    if existing is not None:
+        return _attach_names([existing], db)[0]
+
+    row = NeverSuggest(
+        family_profile_id=payload.family_profile_id,
+        ingredient_id=payload.ingredient_id,
+        recipe_id=payload.recipe_id,
+        reason=_coerce_reason(payload.reason),
+        notes=payload.notes,
+    )
+    db.add(row)
+    db.commit()
+    db.refresh(row)
+    return _attach_names([row], db)[0]
+
+
+@public_router.delete(
+    "/{ns_id}",
+    status_code=status.HTTP_204_NO_CONTENT,
+    response_class=Response,
+)
+def remove_block(
+    ns_id: UUID,
+    db: Session = Depends(get_db),
+    session: str = Depends(require_session),
+) -> Response:
+    """Family-facing: undo a never-suggest (used by the toast Undo button).
+
+    require_session resolves to the auto-detected family id. The row's
+    family_profile_id must match — otherwise a 403 prevents one family
+    from removing another family's block.
+    """
+    row = db.query(NeverSuggest).filter(NeverSuggest.id == ns_id).first()
+    if row is None:
+        raise HTTPException(status_code=404, detail="never-suggest entry not found")
+    if str(row.family_profile_id) != session:
+        raise HTTPException(
+            status_code=403,
+            detail="never-suggest entry belongs to a different family",
+        )
+    db.delete(row)
+    db.commit()
+    return Response(status_code=204)
 
 
 @admin_router.post("", response_model=NeverSuggestRead, status_code=status.HTTP_201_CREATED)
@@ -53,7 +155,7 @@ def block(payload: NeverSuggestCreate, db: Session = Depends(get_db)):
     db.add(row)
     db.commit()
     db.refresh(row)
-    return row
+    return _attach_names([row], db)[0]
 
 
 @admin_router.delete(