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/models/product.py

@@ -1,5 +1,5 @@
 from datetime import date, datetime
-from typing import ClassVar, Optional
+from typing import Any, ClassVar, Optional, cast
 from uuid import UUID, uuid4
 
 from pydantic import field_validator, model_validator
@@ -160,7 +160,6 @@ class Product(SQLModel, table=True):
     is_tool: bool = Field(default=False)
     needle_length_mm: float | None = Field(default=None, gt=0)
 
-    personal_rating: int | None = Field(default=None, ge=1, le=10)
     personal_tolerance_notes: str | None = None
     personal_repurchase_intent: bool | None = None
 
@@ -181,7 +180,7 @@ class Product(SQLModel, table=True):
     @classmethod
     def coerce_effect_profile(cls, v: object) -> object:
         if isinstance(v, dict):
-            return ProductEffectProfile(**v)
+            return ProductEffectProfile(**cast(dict[str, Any], v))
         return v
 
     @model_validator(mode="after")
@@ -324,8 +323,6 @@ class Product(SQLModel, table=True):
         if self.usage_notes:
             ctx["usage_notes"] = self.usage_notes
 
-        if self.personal_rating is not None:
-            ctx["personal_rating"] = self.personal_rating
         if self.personal_tolerance_notes:
             ctx["personal_tolerance_notes"] = self.personal_tolerance_notes
         if self.personal_repurchase_intent is not None: