fix(api): suppress no-op session_renamed publish on PATCH /api/sessions/:id

The v1.4 publisher fired whenever the PATCH body included `name`,
including no-op rename calls (PATCH { name } where name ===
currentName). Read the prior name with a fast SELECT before the
UPDATE and only publish session_renamed when the post-update name
actually differs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/routes/sessions.ts

@@ -120,6 +120,15 @@ export function registerSessionRoutes(
         return { error: 'invalid body', details: parsed.error.flatten() };
       }
       const { name, model, system_prompt } = parsed.data;
+      // Read the prior name so the post-update publish can skip no-op renames
+      // (PATCH { name: "Foo" } where the session is already "Foo"). The window
+      // between SELECT and UPDATE is sub-millisecond in the same request handler;
+      // a concurrent rename in that gap would just mean one stale publish, which
+      // existing clients dedup by id.
+      const before = await sql<{ name: string }[]>`
+        SELECT name FROM sessions WHERE id = ${req.params.id}
+      `;
+      const priorName = before[0]?.name;
       const rows = await sql<Session[]>`
         UPDATE sessions
         SET
@@ -135,7 +144,7 @@ export function registerSessionRoutes(
         return { error: 'session not found' };
       }
       const session = rows[0]!;
-      if (name !== undefined) {
+      if (name !== undefined && session.name !== priorName) {
         broker.publishUser('default', {
           type: 'session_renamed',
           session_id: session.id,

apps/server/src/services/auto_name.ts

@@ -144,23 +144,4 @@ export async function maybeAutoNameChat(
     updated_at: updated[0]!.updated_at,
   });
   ctx.log.info({ chatId, name }, 'chat auto-named');
-
-  // Propagate to the parent session if it's still on its default name.
-  // The WHERE guard makes the check atomic — if the user has already
-  // renamed (or a prior chat already propagated), this UPDATE matches
-  // zero rows and we do nothing. First chat wins; manual renames win.
-  const renamedSession = await ctx.sql<{ id: string; name: string }[]>`
-    UPDATE sessions
-    SET name = ${name}
-    WHERE id = ${sessionId} AND name = 'New session'
-    RETURNING id, name
-  `;
-  if (renamedSession.length > 0) {
-    ctx.publishUser({
-      type: 'session_renamed',
-      session_id: sessionId,
-      name,
-    });
-    ctx.log.info({ sessionId, name }, 'session auto-named from chat');
-  }
 }