refactor: Modularize recipe generator

- Split generate_recipe.py into cli.py, recipe_generator.py, validators.py, manifest.py
- Removed override logic - modifiers now add fragments rather than replace
- Added filename deduplication to prevent overwriting recipes
- Updated CI workflows and tests to use new module structure
- Made pykickstart a hard dependency
- Removed ingredients/ directory support (only fragments/*.ks now used)
- New layout: 5 modules (~990 lines) vs single 769-line file

.gitea/workflows/validate-recipes.yaml

@@ -23,22 +23,22 @@ jobs:
       
       - name: Generate all recipes
         run: |
-          cd scripts
+          cd recipe-generator
           make generate-recipes
       
       - name: Validate recipes (strict mode)
         run: |
-          cd scripts
+          cd recipe-generator
           python3 generate_recipe.py --validate ../recipes/*.cfg --strict
       
       - name: Run unit tests
         run: |
-          cd scripts
+          cd recipe-generator
           make test
       
       - name: Run integration tests
         run: |
-          cd scripts
+          cd recipe-generator
           make test-integration
       
       - name: Upload test results