refactor: remove personal_rating, DRY get_or_404, fix ty errors

- Drop Product.personal_rating from model, API schemas, and all frontend
  views (list table, detail view, quick-edit form, new-product form)
- Extract get_or_404 into backend/innercontext/api/utils.py; remove five
  duplicate copies from individual API modules
- Fix all ty type errors: generic get_or_404 with TypeVar, cast() in
  coerce_effect_profile validator, col() for ilike on SQLModel column,
  dict[str, Any] annotation in test helper, ty: ignore for CORSMiddleware

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/innercontext/api/skincare.py

@@ -6,6 +6,7 @@ from fastapi import APIRouter, Depends, HTTPException
 from sqlmodel import Session, SQLModel, select
 
 from db import get_session
+from innercontext.api.utils import get_or_404
 from innercontext.models import SkinConditionSnapshot
 from innercontext.models.enums import (
     BarrierState,
@@ -66,13 +67,6 @@ class SnapshotUpdate(SQLModel):
 # ---------------------------------------------------------------------------
 
 
-def get_or_404(session: Session, model, record_id) -> object:
-    obj = session.get(model, record_id)
-    if obj is None:
-        raise HTTPException(status_code=404, detail=f"{model.__name__} not found")
-    return obj
-
-
 # ---------------------------------------------------------------------------
 # Routes
 # ---------------------------------------------------------------------------