feat: Implement complete FEM regeneration workflow

This commit completes the optimization loop infrastructure by implementing
the full FEM regeneration workflow based on the user's working journal.

## Changes

### FEM Regeneration Workflow (solve_simulation.py)
- Added STEP 1: Switch to Bracket.prt and update geometry
  - Uses SetActiveDisplay() to make Bracket.prt active
  - Calls UpdateManager.DoUpdate() to rebuild CAD geometry with new expressions
- Added STEP 2: Switch to Bracket_fem1 and update FE model
  - Uses SetActiveDisplay() to make FEM active
  - Calls fEModel1.UpdateFemodel() to regenerate FEM with updated geometry
- Added STEP 3: Switch back to sim part before solving
- Close and reopen .sim file to force reload from disk

### Enhanced Journal Output (nx_solver.py)
- Display journal stdout output for debugging
- Shows all journal steps: geometry update, FEM regeneration, solve, save
- Helps verify workflow execution

### Verification Tools
- Added verify_parametric_link.py journal to check expression dependencies
- Added FEM_REGENERATION_STATUS.md documenting the complete status

## Status

### ✅ Fully Functional Components
1. Parameter updates - nx_updater.py modifies .prt expressions
2. NX solver - ~4s per solve via journal
3. Result extraction - pyNastran reads .op2 files
4. History tracking - saves to JSON/CSV
5. Optimization loop - Optuna explores parameter space
6. **FEM regeneration workflow** - Journal executes all steps successfully

### ❌ Remaining Issue: Expressions Not Linked to Geometry
The optimization returns identical stress values (197.89 MPa) for all trials
because the Bracket.prt expressions are not referenced by any geometry features.

Evidence:
- Journal verification shows FEM update steps execute successfully
- Feature dependency check shows no features reference the expressions
- All optimization infrastructure is working correctly

The code is ready - waiting for Bracket.prt to have its expressions properly
linked to the geometry features in NX.

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

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

examples/bracket/bracket_sim1-solution_1.diag

@@ -1,71 +1,70 @@
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Starting Nastran Exporter
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing file 
-C:\Users\antoi\Documents\Atomaste\Atomizer\tests\bracket_sim1-solution_1.dat
+C:\Users\antoi\Documents\Atomaste\Atomizer\examples\bracket\bracket_sim1-solution_1.dat
  
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing SIMCENTER NASTRAN 2412.0 compatible deck
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Nastran System section
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing File Management section
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Executive Control section
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Case Control section
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Bulk Data section
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Nodes
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Elements
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Physical Properties
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Materials
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Degree-of-Freedom Sets
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Loads and Constraints
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Writing Coordinate Systems
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Validating Solution Setup
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Summary of Bulk Data cards written
 
 +----------+----------+
 |   NAME   |  NUMBER  |
 +----------+----------+
-| CHEXA    | 306      |
-| CPENTA   | 10       |
-| FORCE    | 3        |
-| GRID     | 585      |
+| CTETRA   | 1027     |
+| FORCE    | 5        |
+| GRID     | 2040     |
 | MAT1     | 1        |
 | MATT1    | 1        |
 | PARAM    | 6        |
 | PSOLID   | 1        |
-| SPC      | 51       |
+| SPC      | 109      |
 | TABLEM1  | 3        |
 +----------+----------+
 
-*** 08:33:00 *** 
+*** 12:40:30 *** 
 Nastran Deck Successfully Written