Update mechanical folder structure for multiple sub-assemblies

- Refactor mechanical/ directory to support multiple sub-assemblies instead of just enclosures
- Update mechanical/README.md with comprehensive sub-assembly organization examples
- Enhance mechanical/cad/README.md with detailed sub-assembly structure (PCB mounts, sensor housing, connector panels, cooling, etc.)
- Expand mechanical/enclosure/README.md to cover main housing, sub-enclosures, and removable panels
- Improve mechanical/stl/README.md with broader 3D printing categories including tooling, prototyping, and custom components
- Update mechanical/drawings/README.md with comprehensive technical drawing organization for all mechanical components
- Add detailed manufacturing considerations, quality control procedures, and file management guidelines
- Support complex projects with multiple mechanical sub-systems and assemblies

mechanical/README.md

@@ -1,3 +1,75 @@
 # /mechanical
 
-Mechanical design including enclosures and 3D files.
+Mechanical design files for all physical components and sub-assemblies.
+
+## Purpose
+This directory contains mechanical design files for the complete physical system, including multiple sub-assemblies, enclosures, mounting hardware, and mechanical interfaces.
+
+## Directory Structure
+- `cad/` - Editable CAD models and assemblies
+- `drawings/` - 2D technical drawings and specifications
+- `enclosure/` - Housing and case designs
+- `stl/` - 3D printable files for all components
+
+## Sub-Assembly Organization
+For projects with multiple mechanical sub-assemblies, organize by function:
+
+```
+mechanical/
+├── cad/
+│   ├── main-assembly/          # Complete system assembly
+│   ├── pcb-mount/              # PCB mounting and brackets
+│   ├── sensor-housing/         # Sensor enclosures and mounts
+│   ├── connector-panel/        # Connector panels and interfaces
+│   ├── cooling/                # Heat sinks, fans, thermal management
+│   └── fasteners/              # Custom bolts, spacers, hardware
+├── drawings/
+│   ├── assembly-drawings/      # Overall assembly drawings
+│   ├── detail-drawings/        # Individual part drawings
+│   ├── interface-drawings/     # Mating part specifications
+│   └── manufacturing-drawings/ # Fabrication specifications
+├── enclosure/
+│   ├── main-housing/           # Primary enclosure
+│   ├── sub-enclosures/         # Secondary housings
+│   └── covers-panels/          # Removable covers and access panels
+└── stl/
+    ├── enclosure-parts/        # 3D printable enclosure components
+    ├── mounting-hardware/      # Custom brackets and mounts
+    ├── prototyping/            # Prototype and test fixtures
+    └── tooling/                # Assembly jigs and fixtures
+```
+
+## File Types
+- **CAD Files**: Native CAD formats (.sldprt, .step, .iges, .f3d)
+- **Drawings**: PDF technical drawings and DXF files
+- **3D Models**: STL files for 3D printing, STEP for manufacturing
+- **Assembly Files**: Complete system assemblies and sub-assemblies
+
+## Design Considerations
+- **Modularity**: Design for easy assembly and maintenance
+- **Manufacturing**: Consider fabrication methods and tolerances
+- **Materials**: Document material specifications and requirements
+- **Interfaces**: Define mechanical interfaces between sub-assemblies
+- **Thermal**: Account for heat dissipation and airflow
+- **Accessibility**: Ensure access for assembly, service, and repair
+
+## CAD File Management
+- Use consistent naming conventions across all files
+- Maintain assembly hierarchy and relationships
+- Include material properties and finish specifications
+- Document design intent and critical dimensions
+- Version control CAD files with descriptive commit messages
+
+## Manufacturing Integration
+- Coordinate with PCB dimensions and mounting holes
+- Consider assembly sequence and tooling requirements
+- Define tolerances and critical dimensions
+- Specify surface finishes and treatments
+- Include inspection and quality requirements
+
+## Documentation Requirements
+- Assembly instructions and procedures
+- Bill of materials for mechanical components
+- Interface specifications and mating requirements
+- Manufacturing and fabrication notes
+- Testing and validation procedures