fix: Correct all NX installation paths from Simcenter3D_2412 to NX2412

CRITICAL PATH CORRECTION:
- Updated all documentation to use NX2412 installation
- Fixed README.md, dashboard/api/app.py, NXOPEN_INTELLISENSE_SETUP.md
- Updated archived NX_SOLVER_INTEGRATION.md for consistency
- Added SYSTEM_CONFIGURATION.md to document correct paths

Files Changed:
- README.md: NX path corrected to NX2412\NXBIN\run_journal.exe
- dashboard/api/app.py: NX executable path updated
- docs/NXOPEN_INTELLISENSE_SETUP.md: Stub path corrected
- docs/archive/NX_SOLVER_INTEGRATION.md: Example paths updated
- docs/SYSTEM_CONFIGURATION.md: NEW - Critical system path documentation

Key Configuration:
- Python Environment: atomizer (NOT test_env)
- NX Installation: C:\Program Files\Siemens\NX2412
- Material Library: NX2412\UGII\materials\physicalmateriallibrary.xml
- Python Stubs: NX2412\ugopen\pythonStubs

Reason: Simcenter3D_2412 is a separate installation and should not be used.
NX2412 is the correct primary CAD/CAE environment.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -89,7 +89,7 @@ Atomizer enables engineers to:
    ```
 
 4. **Configure NX path** (edit if needed):
-   - Default NX path: `C:\Program Files\Siemens\Simcenter3D_2412\NXBIN\run_journal.exe`
+   - Default NX path: `C:\Program Files\Siemens\NX2412\NXBIN\run_journal.exe`
    - Update in `optimization_engine/nx_solver.py` if different
 
 ### Basic Usage