feat(ui): project drill-down route with repo-filtered event timeline

Add repo filter param to /v1/events (SQL COALESCE across payload
shapes per source). New /project/:source/* route renders a filtered
activity timeline for a single repo. Dashboard cards link to the
drill-down page.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/DashPage.tsx

@@ -1,4 +1,5 @@
 import { useQuery } from '@tanstack/react-query';
+import { Link } from 'react-router-dom';
 import Col from 'react-bootstrap/Col';
 import Row from 'react-bootstrap/Row';
 
@@ -31,16 +32,9 @@ export function DashPage() {
       <Row xs={1} md={2} lg={3} className="g-3">
         {ranked.map((p) => (
           <Col key={`${p.source}:${p.repo}`}>
+            <Link to={`/project/${p.source}/${p.repo}`} className="text-decoration-none">
             <div className="project-card p-3">
-              <h5 className="mb-1">
-                <a
-                  href={repoUrl(p)}
-                  target="_blank"
-                  rel="noopener noreferrer"
-                >
-                  {p.repo}
-                </a>
-              </h5>
+              <h5 className="mb-1">{p.repo}</h5>
               <small className="text-muted d-block mb-2">{p.source}</small>
               <div className="d-flex gap-3" style={{ fontSize: '0.8rem' }}>
                 {p.commit_count > 0 && <span>{p.commit_count} commits</span>}
@@ -51,6 +45,7 @@ export function DashPage() {
                 {formatRange(p.first_activity, p.last_activity)}
               </div>
             </div>
+            </Link>
           </Col>
         ))}
       </Row>
@@ -58,21 +53,6 @@ export function DashPage() {
   );
 }
 
-function repoUrl(p: ProjectSummary): string {
-  switch (p.source) {
-    case 'github':
-      return `https://github.com/${p.repo}`;
-    case 'gitea':
-      return `https://${p.host}/${p.repo}`;
-    case 'hg':
-      return `https://${p.host}/${p.repo}`;
-    case 'bugzilla':
-      return `https://${p.host}`;
-    default:
-      return '#';
-  }
-}
-
 function formatRange(first: string | null, last: string | null): string {
   const fmt = (iso: string) =>
     new Date(iso).toLocaleDateString('en-GB', { month: 'short', year: 'numeric' }).toLowerCase();