refactor: rename fragments directory to ingredients and update all references

- Directory rename: fragments/ → ingredients/ (54 .ks files)
- Updated all Python scripts:
  * tests/integration/conftest.py - fixture renames
  * tests/integration/test_integration.py - constant and path updates
  * tests/test_recipe_generator.py - updated test assertions
  * recipe-generator/validators.py - updated comments and error messages
  * recipe-generator/recipe_generator.py - updated comment
- Updated all YAML files:
  * recipe-generator/recipe_templates.yaml - 66 path references
  * .gitea/workflows/validate-fragments.yaml → validate-ingredients.yaml
  * .gitea/workflows/test-generation.yaml - path patterns
- Updated scripts:
  * bin/ksflatten-relative - updated path detection
- Updated test file:
  * tests/integration/test_fragments.py → test_ingredients.py
- Updated documentation:
  * DEVELOPMENT.md - simplified references
  * DEVELOPMENT_QUICK.md - updated examples
  * tests/container/README.md - test references
- Regenerated all recipes (16 files) with ingredient paths
- Updated test fixtures (7 files)
- All integration tests pass (5/5)
- All unit tests pass (29/31 - 2 pre-existing failures unrelated)

bin/ksflatten-relative

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 """
 Flatten kickstart recipes with relative %include paths.
-Converts %include fragments/... to %include ../fragments/... relative to recipes/ location.
+Converts %include ingredients/... to %include ../ingredients/... relative to recipes/ location.
 """
 
 import os
@@ -27,10 +27,10 @@ def flatten_recipe(recipe_path, output_path):
             if len(parts) >= 2:
                 fragment_path = parts[1]
                 # Make it relative to recipes/
-                if fragment_path.startswith('fragments/'):
+                if fragment_path.startswith('ingredients/'):
                     # Keep as relative path - it's relative to the recipe file's location
-                    # recipes/ contains recipes, fragments/ is at project root level
-                    # So from recipes/, fragments/ is ../fragments/
+                    # recipes/ contains recipes, ingredients/ is at project root level
+                    # So from recipes/, ingredients/ is ../ingredients/
                     relative_path = '../' + fragment_path
                     lines.append('%include ' + relative_path)
                 else: