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/services/vendor_theme_service.py

@@ -8,21 +8,24 @@ Handles theme CRUD operations, preset application, and validation.
 
 import logging
 import re
-from typing import Dict, List, Optional
 
 from sqlalchemy.orm import Session
 
-from app.core.theme_presets import (THEME_PRESETS, apply_preset,
-                                    get_available_presets, get_preset_preview)
+from app.core.theme_presets import (
+    THEME_PRESETS,
+    apply_preset,
+    get_available_presets,
+    get_preset_preview,
+)
 from app.exceptions.vendor import VendorNotFoundException
-from app.exceptions.vendor_theme import (InvalidColorFormatException,
-                                         InvalidFontFamilyException,
-                                         InvalidThemeDataException,
-                                         ThemeOperationException,
-                                         ThemePresetAlreadyAppliedException,
-                                         ThemePresetNotFoundException,
-                                         ThemeValidationException,
-                                         VendorThemeNotFoundException)
+from app.exceptions.vendor_theme import (
+    InvalidColorFormatException,
+    InvalidFontFamilyException,
+    ThemeOperationException,
+    ThemePresetNotFoundException,
+    ThemeValidationException,
+    VendorThemeNotFoundException,
+)
 from models.database.vendor import Vendor
 from models.database.vendor_theme import VendorTheme
 from models.schema.vendor_theme import ThemePresetPreview, VendorThemeUpdate
@@ -77,7 +80,7 @@ class VendorThemeService:
     # THEME RETRIEVAL
     # ============================================================================
 
-    def get_theme(self, db: Session, vendor_code: str) -> Dict:
+    def get_theme(self, db: Session, vendor_code: str) -> dict:
         """
         Get theme for vendor. Returns default if no custom theme exists.
 
@@ -107,7 +110,7 @@ class VendorThemeService:
 
         return theme.to_dict()
 
-    def _get_default_theme(self) -> Dict:
+    def _get_default_theme(self) -> dict:
         """
         Get default theme configuration.
 
@@ -329,7 +332,7 @@ class VendorThemeService:
                 operation="apply_preset", vendor_code=vendor_code, reason=str(e)
             )
 
-    def get_available_presets(self) -> List[ThemePresetPreview]:
+    def get_available_presets(self) -> list[ThemePresetPreview]:
         """
         Get list of available theme presets.
 
@@ -351,7 +354,7 @@ class VendorThemeService:
     # THEME DELETION
     # ============================================================================
 
-    def delete_theme(self, db: Session, vendor_code: str) -> Dict:
+    def delete_theme(self, db: Session, vendor_code: str) -> dict:
         """
         Delete custom theme for vendor (reverts to default).