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/stl/README.md

@@ -1,3 +1,121 @@
 # /mechanical/stl
 
-Exported STL files ready for printing.
+3D printable files for all mechanical components and sub-assemblies.
+
+## Purpose
+This directory contains STL files ready for 3D printing, organized by functional categories. These files support prototyping, custom tooling, replacement parts, and production components.
+
+## Organization by Function
+Organize STL files by their intended use and sub-assembly:
+
+```
+stl/
+├── enclosure-parts/            # 3D printable enclosure components
+│   ├── housing-prototypes/
+│   ├── custom-panels/
+│   ├── mounting-brackets/
+│   └── access-covers/
+├── mounting-hardware/          # Custom brackets and mounting solutions
+│   ├── pcb-mounts/
+│   ├── sensor-brackets/
+│   ├── cable-management/
+│   └── standoffs-spacers/
+├── prototyping/                # Prototype and development parts
+│   ├── concept-models/
+│   ├── fit-test-parts/
+│   ├── functional-prototypes/
+│   └── design-iterations/
+├── tooling/                    # Assembly and manufacturing aids
+│   ├── assembly-jigs/
+│   ├── test-fixtures/
+│   ├── alignment-tools/
+│   └── handling-fixtures/
+├── replacement-parts/          # Service and maintenance components
+│   ├── wear-parts/
+│   ├── consumables/
+│   └── field-replaceable/
+└── custom-components/          # Project-specific mechanical parts
+    ├── actuator-parts/
+    ├── interface-components/
+    ├── structural-elements/
+    └── specialty-hardware/
+```
+
+## File Naming Convention
+Use descriptive names that include key specifications:
+- `PCB-Mount-Bracket_M3-Holes_v2.1.stl`
+- `Sensor-Housing-Top_IP65_ABS.stl`
+- `Cable-Gland_PG16_TPU-Flexible.stl`
+- `Assembly-Jig_Main-PCB_PLA.stl`
+
+## Print Settings Documentation
+Include recommended print settings for each component:
+
+### Material Recommendations
+- **PLA**: Prototyping, non-critical parts, tooling
+- **PETG**: Mechanical parts, chemical resistance
+- **ABS**: Structural components, higher temperature resistance
+- **TPU**: Flexible parts, gaskets, vibration dampening
+- **ASA**: Outdoor use, UV resistance
+- **PC**: High strength, high temperature applications
+
+### Print Quality Settings
+Document recommended settings for each part:
+- **Layer Height**: 0.1mm (fine), 0.2mm (standard), 0.3mm (draft)
+- **Infill**: 10-20% (light), 40-60% (standard), 80-100% (structural)
+- **Support**: Required/not required, support type
+- **Orientation**: Optimal print orientation for strength/finish
+- **Post-Processing**: Required finishing operations
+
+## Quality Control
+### Print Validation
+- **Dimensional Accuracy**: Critical dimensions and tolerances
+- **Surface Finish**: Required surface quality
+- **Mechanical Properties**: Strength and durability requirements
+- **Fit and Function**: Assembly and mating requirements
+
+### Testing Procedures
+- **Fit Testing**: Verify assembly with mating parts
+- **Functional Testing**: Confirm operational requirements
+- **Durability Testing**: Lifecycle and wear testing
+- **Environmental Testing**: Temperature and chemical resistance
+
+## Manufacturing Notes
+### Production Considerations
+- **Print Time**: Estimated printing duration
+- **Material Usage**: Filament consumption estimates
+- **Batch Production**: Multiple part printing strategies
+- **Quality Assurance**: Inspection and acceptance criteria
+
+### Alternative Manufacturing
+Document when injection molding or machining might be preferred:
+- **Volume Thresholds**: When to consider other processes
+- **Material Limitations**: Properties not achievable with 3D printing
+- **Tolerance Requirements**: Precision beyond 3D printing capabilities
+- **Surface Finish**: Requirements for smooth or textured surfaces
+
+## File Management
+### Version Control
+- Include version numbers in filenames
+- Document changes in commit messages
+- Tag releases for production parts
+- Maintain design history and rationale
+
+### Source File References
+- Link STL files to source CAD files
+- Document any modifications made for 3D printing
+- Include original design intent and specifications
+- Reference assembly drawings and instructions
+
+## Print Instructions
+### Setup Requirements
+- **Printer Specifications**: Minimum build volume and capabilities
+- **Material Preparation**: Drying and storage requirements
+- **Bed Preparation**: Adhesion and leveling requirements
+- **Environmental Conditions**: Temperature and humidity control
+
+### Post-Processing
+- **Support Removal**: Techniques and tools required
+- **Surface Finishing**: Sanding, smoothing, or coating
+- **Assembly Preparation**: Drilling, tapping, or fitting operations
+- **Quality Inspection**: Dimensional and visual checks