Add configuration for cron key and document code style conventions

- Added cron key to config.php for scheduled tasks.
- Created code_style_and_conventions.md to outline PHP version, file naming, DI pattern, controller wiring, Medoo ORM pitfalls, test conventions, caching, and database structure.
- Added project_overview.md detailing the purpose, tech stack, architecture, entry points, and key classes of the shopPRO project.
- Introduced suggested_commands.md for testing and system utilities commands.
- Added task_completion_checklist.md for a structured approach to completing tasks.
- Included .DS_Store files in autoload and templates directories for macOS compatibility.

.serena/memories/suggested_commands.md

@@ -0,0 +1,41 @@
+# Suggested Commands
+
+## Testing
+```bash
+# Full test suite (recommended, PowerShell)
+./test.ps1
+
+# Specific test file
+./test.ps1 tests/Unit/Domain/Product/ProductRepositoryTest.php
+
+# Specific test method
+./test.ps1 --filter testGetQuantityReturnsCorrectValue
+
+# Via composer
+composer test
+```
+
+## System Utilities (Windows with Git Bash)
+```bash
+# Use Unix-style commands (Git Bash shell)
+ls          # list directory
+grep -r     # search content (prefer Serena tools instead)
+git status  # git operations
+git log --oneline -10
+git diff
+git add <file>
+git commit -m "message"
+git push
+```
+
+## Development
+```bash
+# No build step — PHP is interpreted
+# No linting/formatting tool configured
+# Entry points are served via web server (XAMPP)
+```
+
+## PHP binary
+```
+C:\xampp\php\php.exe
+```