feat: Phase 8 Feedback UI + API endpoints

- New backend/app/api/feedback.py: GET/POST for meal_plan_item feedback
- MealDetail.tsx: star rating, never-suggest checkbox, reason dropdown,
  free-text comments, displays saved feedback
- frontend/src/api/index.ts + types: feedback API + TypeScript interface
- backend/app/schemas/__init__.py: model_validator maps qty→quantity for
  RecipeIngredient (fixes Pydantic validation on recipe JSONB)
- docs/HANDOFF.md: mark Phase 8 complete, update file map and date

backend/app/api/feedback.py

@@ -0,0 +1,84 @@
+from __future__ import annotations
+
+from uuid import UUID
+
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app.models import FamilyProfile, Feedback, MealPlanItem
+from app.schemas import FeedbackCreate, FeedbackResponse
+from app.security import require_session
+
+router = APIRouter()
+
+
+@router.get("/{meal_plan_item_id}", response_model=FeedbackResponse | None)
+def get_feedback(
+    meal_plan_item_id: UUID,
+    db: Session = Depends(get_db),
+    family_id: str = Depends(require_session),
+):
+    """Get existing feedback for a meal plan item."""
+    item = db.query(MealPlanItem).filter(MealPlanItem.id == meal_plan_item_id).first()
+    if not item:
+        raise HTTPException(status_code=404, detail="Meal plan item not found")
+
+    feedback = (
+        db.query(Feedback)
+        .filter(
+            Feedback.meal_plan_item_id == meal_plan_item_id,
+            Feedback.family_profile_id == UUID(family_id),
+        )
+        .first()
+    )
+    return feedback
+
+
+@router.post("", response_model=FeedbackResponse)
+def create_feedback(
+    data: FeedbackCreate,
+    db: Session = Depends(get_db),
+    family_id: str = Depends(require_session),
+):
+    """Create or update feedback for a meal plan item."""
+    item = db.query(MealPlanItem).filter(
+        MealPlanItem.id == data.meal_plan_item_id
+    ).first()
+    if not item:
+        raise HTTPException(status_code=404, detail="Meal plan item not found")
+
+    profile = db.query(FamilyProfile).filter(FamilyProfile.id == UUID(family_id)).first()
+    if not profile:
+        raise HTTPException(status_code=404, detail="Family profile not found")
+
+    existing = (
+        db.query(Feedback)
+        .filter(
+            Feedback.meal_plan_item_id == data.meal_plan_item_id,
+            Feedback.family_profile_id == UUID(family_id),
+        )
+        .first()
+    )
+
+    if existing:
+        existing.rating = data.rating
+        existing.never_suggest = data.never_suggest
+        existing.denial_reason = data.denial_reason.value if data.denial_reason else None
+        existing.feedback_text = data.feedback_text
+        db.commit()
+        db.refresh(existing)
+        return existing
+
+    feedback = Feedback(
+        family_profile_id=UUID(family_id),
+        meal_plan_item_id=data.meal_plan_item_id,
+        rating=data.rating,
+        never_suggest=data.never_suggest,
+        denial_reason=data.denial_reason.value if data.denial_reason else None,
+        feedback_text=data.feedback_text,
+    )
+    db.add(feedback)
+    db.commit()
+    db.refresh(feedback)
+    return feedback