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>

crates/moments-data/src/lib.rs

@@ -54,6 +54,12 @@ impl EventReader for PgStore {
               AND ($2::timestamptz IS NULL OR occurred_at <  $2)
               AND ($3::text[]      IS NULL OR source = ANY($3))
               AND ($4::bool        OR public = true)
+              AND ($6::text IS NULL OR COALESCE(
+                    payload->'repo'->>'name',
+                    payload->'repository'->>'full_name',
+                    payload->>'_repo',
+                    payload->>'product'
+                  ) = $6)
             ORDER BY occurred_at DESC
             LIMIT $5
             "#,
@@ -63,6 +69,7 @@ impl EventReader for PgStore {
         .bind(sources.as_deref())
         .bind(query.include_private)
         .bind(query.limit as i64)
+        .bind(query.repo.as_deref())
         .fetch_all(&self.pool)
         .await
         .map_err(map_err)?;