docs: Replace Black and isort references with Ruff in steering docs

- Update tech.md to reference Ruff as combined linter and formatter
- Update structure.md to use Ruff for formatting and import sorting
- Maintain 79-character line length configuration
- Preserve Django-aware import sorting documentation

Author: karbassi

.kiro/specs/black-to-ruff-migration/tasks.md

@@ -18,22 +18,22 @@
   - Keep all other pre-commit hooks unchanged (trailing-whitespace, end-of-file-fixer, etc.)
   - _Requirements: 2.1, 2.2, 2.3, 2.4_
 
-- [ ] 3. Update documentation files
-- [ ] 3.1 Update .kiro/steering/tech.md
+- [x] 3. Update documentation files
+- [x] 3.1 Update .kiro/steering/tech.md
 
   - Replace Black and isort references with Ruff in Code Quality Tools section
   - Update tool descriptions to reflect Ruff's combined formatting and linting capabilities
   - Maintain 79-character line length documentation
   - _Requirements: 3.1, 3.6_
 
-- [ ] 3.2 Update .kiro/steering/structure.md
+- [x] 3.2 Update .kiro/steering/structure.md
 
   - Replace Black formatter references with Ruff in Development Conventions section
   - Update code style documentation to reference Ruff instead of Black and isort
   - Maintain Django-aware import sorting documentation
   - _Requirements: 3.2, 3.6_
 
-- [ ] 3.3 Check and update README.md if needed
+- [x] 3.3 Check and update README.md if needed
 
   - Search for any references to Black or isort in README.md
   - Update developer setup instructions to include Ruff-specific commands if present

.kiro/steering/structure.md

@@ -91,8 +91,8 @@ Extends django-allauth for custom authentication:
 
 ### Code Style
 
-- Black formatter with 79 character line length
-- isort for import organization with Django-aware sections
+- Ruff formatter and linter with 79 character line length
+- Ruff import sorting with Django-aware sections
 - Migrations excluded from formatting
 
 ### Database

.kiro/steering/tech.md

@@ -25,8 +25,7 @@
 
 ## Code Quality Tools
 
-- **Black** - Code formatter (line length: 79)
-- **isort** - Import sorting with Black profile
+- **Ruff** - Fast Python linter and formatter with import sorting (line length: 79)
 - **django-nose** - Test runner
 
 ## Common Commands