Refine repository structure for KiCad 9 optimization

- Add dedicated /kicad/ directory with organized subdirectories for libraries, schematics, gerbers, plots, and backups
- Create comprehensive KiCad 9 library structure (symbols, footprints, 3D models)
- Add manufacturing-ready directories for production files (gerbers, drill, pick-and-place)
- Update all README files with KiCad-specific documentation and workflows
- Add KiCad-optimized .gitignore file for proper version control
- Create KICAD-PROJECT-TEMPLATE.md comprehensive usage guide
- Add hardware assembly documentation and BOM management
- Include detailed manufacturing file generation instructions
- Add docs structure with design-notes and user-manual directories
- Provide complete workflow from design to manufacturing with quality checklists

kicad/schematics/README.md

@@ -0,0 +1,45 @@
+# /kicad/schematics
+
+Additional and hierarchical schematic files for your KiCad project.
+
+## Purpose
+This directory contains supplementary schematic files that are not the main project schematic:
+- Hierarchical sheets (`.kicad_sch` files)
+- Alternative design versions
+- Modular circuit blocks
+- Test circuits
+
+## File Types
+- **`.kicad_sch`**: KiCad 9 schematic files
+- **`.kicad_sch-bak`**: Automatic backup files (excluded from git)
+
+## Hierarchical Design
+When using hierarchical sheets in KiCad:
+1. Create hierarchical sheet symbols in your main schematic
+2. Store the actual sheet files in this directory
+3. Use relative paths when linking sheets
+
+## Naming Convention
+- Use descriptive names for hierarchical sheets
+- Examples:
+  - `power_supply.kicad_sch`
+  - `mcu_core.kicad_sch`
+  - `sensor_interface.kicad_sch`
+  - `communication.kicad_sch`
+
+## Example Structure
+```
+schematics/
+├── power_supply.kicad_sch      # Power management circuit
+├── mcu_core.kicad_sch          # Microcontroller and core components
+├── sensor_interface.kicad_sch  # Sensor connections and conditioning
+├── communication.kicad_sch     # Communication interfaces (UART, SPI, I2C)
+└── test_circuits.kicad_sch     # Test points and debug circuits
+```
+
+## Best Practices
+- Keep hierarchical sheets focused on specific functions
+- Use consistent naming conventions
+- Document sheet purposes in the main schematic
+- Use relative paths for portability
+- Include proper sheet titles and revision information