refactor: modernize code quality tooling with Ruff

- Replace black, isort, and flake8 with Ruff (all-in-one linter and formatter)
- Add comprehensive pyproject.toml configuration
- Simplify Makefile code quality targets
- Configure exclusions for venv/.venv in pyproject.toml
- Auto-fix 1,359 linting issues across codebase

Benefits:
- Much faster builds (Ruff is written in Rust)
- Single tool replaces multiple tools
- More comprehensive rule set (UP, B, C4, SIM, PIE, RET, Q)
- All configuration centralized in pyproject.toml
- Better import sorting and formatting consistency

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/api/v1/vendor/content_pages.py

@@ -9,7 +9,6 @@ Vendors can:
 """
 
 import logging
-from typing import List, Optional
 
 from fastapi import APIRouter, Depends, HTTPException, Query
 from pydantic import BaseModel, Field
@@ -41,10 +40,10 @@ class VendorContentPageCreate(BaseModel):
     content_format: str = Field(
         default="html", description="Content format: html or markdown"
     )
-    meta_description: Optional[str] = Field(
+    meta_description: str | None = Field(
         None, max_length=300, description="SEO meta description"
     )
-    meta_keywords: Optional[str] = Field(
+    meta_keywords: str | None = Field(
         None, max_length=300, description="SEO keywords"
     )
     is_published: bool = Field(default=False, description="Publish immediately")
@@ -56,31 +55,31 @@ class VendorContentPageCreate(BaseModel):
 class VendorContentPageUpdate(BaseModel):
     """Schema for updating a vendor content page."""
 
-    title: Optional[str] = Field(None, max_length=200)
-    content: Optional[str] = None
-    content_format: Optional[str] = None
-    meta_description: Optional[str] = Field(None, max_length=300)
-    meta_keywords: Optional[str] = Field(None, max_length=300)
-    is_published: Optional[bool] = None
-    show_in_footer: Optional[bool] = None
-    show_in_header: Optional[bool] = None
-    display_order: Optional[int] = None
+    title: str | None = Field(None, max_length=200)
+    content: str | None = None
+    content_format: str | None = None
+    meta_description: str | None = Field(None, max_length=300)
+    meta_keywords: str | None = Field(None, max_length=300)
+    is_published: bool | None = None
+    show_in_footer: bool | None = None
+    show_in_header: bool | None = None
+    display_order: int | None = None
 
 
 class ContentPageResponse(BaseModel):
     """Schema for content page response."""
 
     id: int
-    vendor_id: Optional[int]
-    vendor_name: Optional[str]
+    vendor_id: int | None
+    vendor_name: str | None
     slug: str
     title: str
     content: str
     content_format: str
-    meta_description: Optional[str]
-    meta_keywords: Optional[str]
+    meta_description: str | None
+    meta_keywords: str | None
     is_published: bool
-    published_at: Optional[str]
+    published_at: str | None
     display_order: int
     show_in_footer: bool
     show_in_header: bool
@@ -88,8 +87,8 @@ class ContentPageResponse(BaseModel):
     is_vendor_override: bool
     created_at: str
     updated_at: str
-    created_by: Optional[int]
-    updated_by: Optional[int]
+    created_by: int | None
+    updated_by: int | None
 
 
 # ============================================================================
@@ -97,7 +96,7 @@ class ContentPageResponse(BaseModel):
 # ============================================================================
 
 
-@router.get("/", response_model=List[ContentPageResponse])
+@router.get("/", response_model=list[ContentPageResponse])
 def list_vendor_pages(
     include_unpublished: bool = Query(False, description="Include draft pages"),
     current_user: User = Depends(get_current_vendor_api),
@@ -120,7 +119,7 @@ def list_vendor_pages(
     return [page.to_dict() for page in pages]
 
 
-@router.get("/overrides", response_model=List[ContentPageResponse])
+@router.get("/overrides", response_model=list[ContentPageResponse])
 def list_vendor_overrides(
     include_unpublished: bool = Query(False, description="Include draft pages"),
     current_user: User = Depends(get_current_vendor_api),
@@ -284,4 +283,4 @@ def delete_vendor_page(
     # Delete
     content_page_service.delete_page(db, page_id)
 
-    return None
+    return