feat: Add comprehensive study management system to dashboard

Added full study configuration UI:
- Create studies with isolated folder structure (sim/, results/, config.json)
- File management: users drop .sim/.prt files into study's sim folder
- NX expression extraction: journal script to explore .sim file
- Configuration UI for design variables, objectives, and constraints
- Save/load study configurations through API
- Step-by-step workflow: create → add files → explore → configure → run

Backend API (app.py):
- POST /api/study/create - Create new study with folder structure
- GET /api/study/<name>/sim/files - List files in sim folder
- POST /api/study/<name>/explore - Extract expressions from .sim file
- GET/POST /api/study/<name>/config - Load/save study configuration

Frontend:
- New study configuration view with 5-step wizard
- Modal for creating new studies
- Expression explorer with clickable selection
- Dynamic forms for variables/objectives/constraints
- Professional styling with config cards

NX Integration:
- extract_expressions.py journal script
- Scans .sim and all loaded .prt files
- Identifies potential design variable candidates
- Exports expressions with values, formulas, units

Each study is self-contained with its own geometry files and config.

dashboard/frontend/styles.css

@@ -528,6 +528,157 @@ tbody tr:hover {
     color: var(--text-light);
 }
 
+/* Study Configuration */
+.study-config {
+    display: none;
+}
+
+.config-steps {
+    display: flex;
+    flex-direction: column;
+    gap: 2rem;
+}
+
+.config-step {
+    background: var(--bg);
+    border-radius: 12px;
+    padding: 1.5rem;
+    border-left: 4px solid var(--primary);
+}
+
+.config-step h3 {
+    color: var(--text);
+    margin-bottom: 1rem;
+}
+
+.step-description {
+    color: var(--text-light);
+    margin-bottom: 1rem;
+    font-size: 0.95rem;
+}
+
+.step-content {
+    margin-top: 1rem;
+}
+
+.file-info {
+    background: white;
+    padding: 1rem;
+    border-radius: 8px;
+    margin-bottom: 1rem;
+    border: 1px solid var(--border);
+}
+
+.files-list {
+    margin: 1rem 0;
+    max-height: 200px;
+    overflow-y: auto;
+}
+
+.file-item {
+    padding: 0.75rem;
+    background: white;
+    border-radius: 6px;
+    margin-bottom: 0.5rem;
+    border: 1px solid var(--border);
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+}
+
+.file-item .file-name {
+    font-weight: 600;
+}
+
+.file-item .file-meta {
+    font-size: 0.85rem;
+    color: var(--text-light);
+}
+
+.expressions-list {
+    margin-top: 1rem;
+    padding: 1rem;
+    background: white;
+    border-radius: 8px;
+    border: 1px solid var(--border);
+    max-height: 300px;
+    overflow-y: auto;
+}
+
+.expression-item {
+    padding: 0.75rem;
+    background: var(--bg);
+    border-radius: 6px;
+    margin-bottom: 0.5rem;
+    cursor: pointer;
+    border: 2px solid transparent;
+    transition: all 0.2s;
+}
+
+.expression-item:hover {
+    border-color: var(--primary);
+    transform: translateX(4px);
+}
+
+.expression-item.selected {
+    background: linear-gradient(135deg, #667eea20 0%, #764ba220 100%);
+    border-color: var(--primary);
+}
+
+.expression-name {
+    font-weight: 600;
+    margin-bottom: 0.25rem;
+}
+
+.expression-meta {
+    font-size: 0.85rem;
+    color: var(--text-light);
+}
+
+.variables-config, .objectives-config, .constraints-config {
+    margin: 1rem 0;
+}
+
+.config-item {
+    background: white;
+    padding: 1rem;
+    border-radius: 8px;
+    margin-bottom: 1rem;
+    border: 1px solid var(--border);
+}
+
+.config-item-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: 0.75rem;
+}
+
+.config-item-title {
+    font-weight: 600;
+    color: var(--text);
+}
+
+.config-item-remove {
+    background: none;
+    border: none;
+    color: var(--danger);
+    cursor: pointer;
+    font-size: 1.2rem;
+}
+
+.config-item-fields {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
+    gap: 1rem;
+}
+
+.field-inline {
+    display: flex;
+    gap: 1rem;
+    align-items: flex-end;
+}
+
 /* Responsive */
 @media (max-width: 1024px) {
     .main-content {
@@ -541,4 +692,8 @@ tbody tr:hover {
     .charts-container {
         grid-template-columns: 1fr;
     }
+
+    .config-item-fields {
+        grid-template-columns: 1fr;
+    }
 }