Add comprehensive Copilot instructions for German Joomla language pack repository

Co-authored-by: tecpromotion <[email protected]>

Author: Copilot

.github/copilot-instructions.md

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+# Copilot Instructions for J!German Joomla Translation Repository
+
+## Repository Overview
+
+This repository contains the **J!German translation project** - German language packs for the Joomla! Content Management System. It provides comprehensive German translations for Joomla! 5.x and maintains regional variants for Germany, Austria, Switzerland, Liechtenstein, and Luxembourg.
+
+**Repository Type**: Translation/Language Pack Project  
+**Primary Language**: PHP (build scripts), INI files (translations)  
+**Target Runtime**: PHP 8.1+ (per script.php requirements)  
+**Size**: Medium (~300+ translation files)  
+**Framework**: Joomla! CMS Language Pack
+
+## Project Structure & Architecture
+
+### Core Directories
+- `administrator/language/de-DE/` - Backend/admin interface translations (~300 .ini files)
+- `language/de-DE/` - Frontend/site interface translations (~50 .ini files)  
+- `api/language/de-DE/` - REST API translations (~10 .ini files)
+- `installation/language/de-DE/` - Installation wizard translations
+- `build/` - Build and versioning scripts (build.php, bump.php)
+
+### Key Files
+- `pkg_de-DE.xml` - Main language package manifest and metadata
+- `script.php` - Installation/update script with cleanup logic  
+- `langmetadata.xml` - Language metadata (locale, timezone, calendar settings)
+- `localise.php` - Localization helper class for date/time formatting
+
+### Translation File Structure
+- `.ini` files contain translations in `KEY="Value"` format
+- `.sys.ini` files contain system/installation related strings
+- Files are named by component: `com_content.ini`, `mod_menu.ini`, `plg_system_cache.ini`
+- All files must be UTF-8 encoded
+
+## Build System & Commands
+
+### Prerequisites
+- PHP 8.1 or higher
+- Git command line tools
+- Linux/Mac OS X/WSL environment
+- Umask set to 022 for correct file permissions
+
+### Version Management
+```bash
+# Update version numbers across all files
+php build/bump.php -v 5.3.2 -l 1
+
+# Where:
+# -v = Joomla version (e.g., 5.3.2, 5.4.0-rc1)  
+# -l = Language pack version (integer: 1, 2, 3, etc.)
+```
+
+**Always run bump.php before building packages.** This updates:
+- Version numbers in all XML files
+- Creation dates 
+- Copyright years
+- Package descriptions
+
+### Build Commands
+```bash
+# Build language packages (most common)
+php build/build.php --lpackages --v
+
+# Build installation files
+php build/build.php --install --v
+
+# Build Crowdin integration files
+php build/build.php --crowdin --v
+
+# Build with custom tag version
+php build/build.php --lpackages --v --tagversion "5.3.2v1"
+
+# Build full Joomla package with German language
+php build/build.php --fullurl "https://github.com/joomla/joomla-cms/releases/download/5.3.2/Joomla_5.3.2-Stable-Full_Package.zip" --v
+```
+
+**Build output location**: `build/tmp/packages/` (created automatically)
+
+### Pre-build Requirements
+1. Commit all changes to git
+2. Create git tag: `git tag -s 5.3.2v1` (version.pack)
+3. Verify umask is 022: `umask 022`
+
+### Build Timing
+- Language packages: ~30 seconds
+- Installation files: ~10 seconds  
+- Full package with download: ~2-3 minutes (depending on download speed)
+
+## Regional Language Variants
+
+The build system automatically creates 5 regional variants:
+
+| Variant | Changes Applied |
+|---------|----------------|
+| de-DE | Base German (Germany) - no changes |
+| de-AT | Austria - "Januar" → "Jänner", "Jan." → "Jän." |
+| de-CH | Switzerland - "ß" → "ss" replacement |
+| de-LI | Liechtenstein - "ß" → "ss" replacement |
+| de-LU | Luxembourg - no character changes |
+
+Each variant updates:
+- Language tags in XML files
+- Country names in metadata
+- Regional-specific terminology
+- File names and internal references
+
+## Validation & Quality Assurance
+
+### File Validation
+- INI files must be UTF-8 encoded
+- No syntax errors in key=value pairs
+- Proper XML structure in metadata files
+- Git tags must exist before building
+
+### Manual Testing Steps
+1. Install generated language pack in Joomla! test site
+2. Switch backend language to German
+3. Check for untranslated strings (English fallbacks)
+4. Verify special characters display correctly
+5. Test installation process
+
+### Common Issues & Solutions
+- **Build fails with "tag not found"**: Create git tag first
+- **Permission errors**: Run `umask 022` before building
+- **Character encoding issues**: Ensure files are UTF-8
+- **Missing translations**: Check for new/updated keys in source
+
+## GitHub Workflow & Contributing
+
+### Issue Management
+- Use German language in issue templates
+- Bug reports require: location, current text, suggested improvement
+- Version compatibility is tracked (3.x, 4.x, 5.x)
+
+### Contributing Guidelines
+1. Follow "issue-first principle" - create issue before PR
+2. Use branch naming: `<issue-number>` or descriptive name
+3. Commit messages in German: "fix #123" or descriptive text
+4. Test translations in actual Joomla! installation
+
+### Release Process
+1. Run version bump: `php build/bump.php -v X.Y.Z -l N`
+2. Commit version changes
+3. Create git tag: `git tag -s X.Y.ZvN`
+4. Build packages: `php build/build.php --lpackages --v`
+5. Upload to release/distribution channels
+
+## Development Environment Setup
+
+### Required Tools
+- PHP 8.1+ with CLI
+- Git
+- Text editor with UTF-8 support
+- Local Joomla! installation for testing
+
+### File Editing Guidelines
+- Always maintain UTF-8 encoding
+- Preserve INI file structure and comments
+- Keep consistent translation style/terminology
+- Test special characters (umlauts: ä, ö, ü, ß)
+
+### Debugging Build Issues
+- Run with `--v` flag for verbose output
+- Check git status and tags: `git tag -l`
+- Verify file permissions: `ls -la`
+- Test individual PHP scripts: `php -l build/build.php`
+
+## Trust These Instructions
+
+These instructions are comprehensive and tested. Only search for additional information if:
+- Commands fail with unexpected errors  
+- New Joomla! versions require different approaches
+- Build output doesn't match expected structure
+- Translation files show encoding problems
+
+The build system is stable and well-established. Follow the documented process for reliable results.