Add tags prominence and SIM source grouping features

Database changes:
- Add sim_source_id column to artifacts table for grouping multiple artifacts
- Create Alembic migration (001_add_sim_source_id) for schema update
- Add Alembic env.py for migration support with environment-based DB URLs

API enhancements:
- Add sim_source_id parameter to upload endpoint
- Add sim_source_id filter to query endpoint
- Add new /grouped-by-sim-source endpoint for getting artifacts by group
- Update all API documentation to include sim_source_id

UI improvements:
- Make tags required field and more prominent in upload form
- Add tags display directly in artifacts table (below filename)
- Add SIM Source ID field in upload form with helper text for grouping
- Update table to show sim_source_id (falls back to test_suite if null)
- Tags now displayed as inline badges in main table view

Seed data updates:
- Generate sim_source_id for 70% of artifacts to demonstrate grouping
- Multiple artifacts can share same sim_source_id
- Improved seed data variety with tag combinations

Features:
- Tags are now prominently displayed in both table and detail views
- Multiple artifacts can be grouped by SIM source ID
- Users can filter/query by sim_source_id
- Backward compatible - existing artifacts without sim_source_id still work

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

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

static/js/app.js

@@ -73,11 +73,12 @@ function displayArtifacts(artifacts) {
 
     tbody.innerHTML = displayedArtifacts.map(artifact => `
         <tr>
-            <td>${artifact.test_suite || '-'}</td>
+            <td>${artifact.sim_source_id || artifact.test_suite || '-'}</td>
             <td>
                 <a href="#" onclick="showDetail(${artifact.id}); return false;" style="color: #60a5fa; text-decoration: none;">
                     ${escapeHtml(artifact.filename)}
                 </a>
+                ${artifact.tags && artifact.tags.length > 0 ? `<br><div style="margin-top: 5px;">${formatTags(artifact.tags)}</div>` : ''}
             </td>
             <td>${formatDate(artifact.created_at)}</td>
             <td>${artifact.test_name || '-'}</td>
@@ -289,9 +290,9 @@ async function uploadArtifact(event) {
     formData.append('file', fileInput.files[0]);
 
     // Add optional fields
-    const fields = ['test_name', 'test_suite', 'test_result', 'version', 'description'];
+    const fields = ['test_name', 'test_suite', 'test_result', 'version', 'description', 'sim_source_id'];
     fields.forEach(field => {
-        const value = form.elements[field].value;
+        const value = form.elements[field]?.value;
         if (value) formData.append(field, value);
     });