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

docs/design-notes/README.md

@@ -0,0 +1,89 @@
+# /docs/design-notes
+
+Design decisions and technical documentation for your KiCad project.
+
+## Purpose
+This directory contains technical documentation that explains the design decisions, trade-offs, and engineering rationale behind your KiCad project.
+
+## Document Types
+- **Design Requirements**: Project specifications and constraints
+- **Architecture Overview**: High-level system design
+- **Circuit Analysis**: Detailed circuit explanations
+- **Component Selection**: Why specific components were chosen
+- **Design Trade-offs**: Alternative approaches considered
+- **Simulation Results**: SPICE analysis and verification
+- **Design Reviews**: Peer review notes and feedback
+
+## Recommended Files
+```
+design-notes/
+├── requirements.md              # Project requirements and specifications
+├── architecture.md              # System architecture overview
+├── power-design.md              # Power supply design notes
+├── signal-integrity.md          # High-speed design considerations
+├── component-selection.md       # Component choice rationale
+├── thermal-analysis.md          # Thermal design considerations
+├── emc-considerations.md        # EMC/EMI design notes
+├── design-reviews/              # Review meeting notes
+│   ├── review-001-schematic.md
+│   ├── review-002-layout.md
+│   └── review-003-final.md
+└── simulations/                 # Simulation results and analysis
+    ├── power-analysis.md
+    ├── signal-timing.md
+    └── thermal-simulation.md
+```
+
+## Design Requirements Template
+Document your project requirements:
+- **Functional Requirements**: What the system must do
+- **Performance Requirements**: Speed, accuracy, efficiency
+- **Environmental Requirements**: Temperature, humidity, vibration
+- **Regulatory Requirements**: Safety, EMC, certifications
+- **Cost Constraints**: Target BOM cost and volumes
+- **Size Constraints**: Physical dimensions and weight
+- **Interface Requirements**: Connectors, protocols, voltages
+
+## Architecture Documentation
+Describe your system architecture:
+- **Block Diagram**: High-level system overview
+- **Signal Flow**: How data/signals move through system
+- **Power Distribution**: Power supply architecture
+- **Interface Definitions**: External connections
+- **Key Components**: Major ICs and their roles
+- **Design Partitioning**: How functionality is divided
+
+## Component Selection Notes
+Document why components were chosen:
+- **Requirements**: What the component needs to do
+- **Alternatives Considered**: Other options evaluated
+- **Selection Criteria**: Performance, cost, availability
+- **Trade-offs**: Compromises made
+- **Supplier Information**: Primary and alternate sources
+- **Lifecycle Considerations**: Obsolescence risk
+
+## Design Review Process
+Document design reviews:
+- **Review Objectives**: What was being reviewed
+- **Participants**: Who attended the review
+- **Findings**: Issues and concerns identified
+- **Action Items**: Required changes and improvements
+- **Sign-off**: Approval status and next steps
+
+## Simulation and Analysis
+Document analysis work:
+- **Simulation Setup**: Tools and models used
+- **Test Conditions**: Operating conditions simulated
+- **Results**: Key findings and measurements
+- **Interpretation**: What the results mean
+- **Design Impact**: How results influenced design
+- **Verification**: How simulation was validated
+
+## Best Practices
+- Write for future maintainers (including yourself)
+- Include diagrams and schematics where helpful
+- Reference specific component datasheets
+- Document assumptions and limitations
+- Update notes when design changes
+- Use consistent formatting and terminology
+- Include revision history for major changes