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/enclosure/README.md

@@ -1,3 +1,93 @@
 # /mechanical/enclosure
 
-STL/STEP files for 3D-printable enclosures.
+Housing and enclosure designs for the complete system.
+
+## Purpose
+This directory contains enclosure and housing designs that protect and contain the electronic and mechanical components. Enclosures may include multiple housings, covers, and panels depending on system complexity.
+
+## Enclosure Types
+Organize by enclosure function and hierarchy:
+
+```
+enclosure/
+├── main-housing/               # Primary system enclosure
+│   ├── base-housing.sldprt
+│   ├── top-cover.sldprt
+│   ├── gaskets-seals.sldprt
+│   └── housing-assembly.sldasm
+├── sub-enclosures/             # Secondary or modular housings
+│   ├── sensor-module-housing/
+│   ├── power-supply-housing/
+│   ├── interface-module-housing/
+│   └── expansion-module-housing/
+└── covers-panels/              # Removable access components
+    ├── access-panels/
+    ├── connector-panels/
+    ├── display-bezels/
+    └── ventilation-grilles/
+```
+
+## Design Considerations
+
+### Environmental Protection
+- **IP Rating**: Define ingress protection requirements
+- **Sealing**: Gaskets, O-rings, and weatherproofing
+- **Drainage**: Water management and condensation control
+- **Ventilation**: Airflow and thermal management
+
+### Mechanical Requirements
+- **Structural Integrity**: Load bearing and impact resistance
+- **Mounting**: Wall mount, panel mount, or free-standing
+- **Access**: Service panels and component accessibility
+- **Cable Management**: Entry points and strain relief
+
+### Manufacturing Considerations
+- **Material Selection**: Plastic, metal, composite materials
+- **Manufacturing Process**: Injection molding, machining, sheet metal
+- **Tolerances**: Fit and finish requirements
+- **Surface Treatment**: Painting, anodizing, texturing
+
+### Electrical Integration
+- **EMI/RFI Shielding**: Electromagnetic compatibility
+- **Grounding**: Electrical safety and noise reduction
+- **Cable Entry**: Glands, connectors, and feedthroughs
+- **Heat Dissipation**: Thermal interface to internal components
+
+## File Organization
+
+### Main Housing Files
+- **Base/Bottom**: Primary structural component
+- **Cover/Top**: Removable or hinged access
+- **Sides/Walls**: Structural walls and mounting surfaces
+- **Internal Structure**: Mounting posts, ribs, and supports
+
+### Sub-Enclosure Files
+- **Modular Housings**: Self-contained sub-assemblies
+- **Protective Covers**: Component-specific protection
+- **Interface Panels**: User interaction surfaces
+- **Mounting Brackets**: Attachment to main housing
+
+### Hardware and Fasteners
+- **Screws and Bolts**: Fastening hardware specifications
+- **Hinges and Latches**: Access mechanism components
+- **Gaskets and Seals**: Environmental protection components
+- **Inserts and Threads**: Threaded fastening points
+
+## Material Specifications
+Document material requirements for each component:
+- **Mechanical Properties**: Strength, flexibility, durability
+- **Environmental Resistance**: UV, chemical, temperature
+- **Electrical Properties**: Conductivity, dielectric strength
+- **Regulatory Compliance**: UL, CE, RoHS requirements
+
+## Assembly Instructions
+- **Assembly Sequence**: Order of component installation
+- **Torque Specifications**: Fastener tightening requirements
+- **Sealing Procedures**: Gasket installation and verification
+- **Quality Checks**: Dimensional and functional verification
+
+## Testing and Validation
+- **Environmental Testing**: Temperature, humidity, vibration
+- **Ingress Protection**: Water and dust resistance verification
+- **EMC Testing**: Electromagnetic compatibility validation
+- **Mechanical Testing**: Drop, impact, and load testing