feat(agents): sort recent issues by most recent activity including comments

Update addComment to touch issue updatedAt so comment activity is
reflected in recency sorting. Sort assigned issues on agent detail
page by updatedAt desc so the most recently active issues appear first.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/services/issues.ts

@@ -788,7 +788,7 @@ export function issueService(db: Db) {
 
       if (!issue) throw notFound("Issue not found");
 
-      return db
+      const [comment] = await db
         .insert(issueComments)
         .values({
           companyId: issue.companyId,
@@ -797,8 +797,15 @@ export function issueService(db: Db) {
           authorUserId: actor.userId ?? null,
           body,
         })
-        .returning()
-        .then((rows) => rows[0]);
+        .returning();
+
+      // Update issue's updatedAt so comment activity is reflected in recency sorting
+      await db
+        .update(issues)
+        .set({ updatedAt: new Date() })
+        .where(eq(issues.id, issueId));
+
+      return comment;
     },
 
     createAttachment: async (input: {