fix(server): a branch the caller named is not renamed from the first agent context

The daemon marked every new branch-off worktree for automatic naming, recording the chosen branch
as the placeholder, so the first agent's prompt could rename a branch a plugin or client had
named through branchName. Only a branch the daemon derived from the worktree slug is a
placeholder now.

packages/server/src/server/paseo-worktree-service.test.ts

@@ -675,6 +675,40 @@ test("renames the branch even when the app supplies a random placeholder slug",
   expect(branchAfter).toBe("renamed-from-prompt");
 });
 
+test("keeps a branch the caller named instead of renaming it from the first agent context", async () => {
+  const { repoDir, tempDir } = createGitRepo();
+  cleanupPaths.push(tempDir);
+
+  const created = await createPaseoWorktree(
+    {
+      cwd: repoDir,
+      worktreeSlug: "dazzling-yak",
+      branchName: "pas-101-slow-sidebar",
+      firstAgentContext: { prompt: "Investigate the failing login flow" },
+
+      paseoHome: path.join(tempDir, ".paseo"),
+    },
+    createDeps(),
+  );
+
+  expect(created.worktree.branchName).toBe("pas-101-slow-sidebar");
+  await expect(
+    attemptFirstAgentBranchAutoName({
+      cwd: created.worktree.worktreePath,
+      firstAgentContext: { prompt: "Investigate the failing login flow" },
+      generateBranchNameFromContext: async () => "must-not-rename",
+    }),
+  ).resolves.toEqual({ attempted: false, renamed: false, branchName: null });
+  expect(
+    execFileSync("git", ["branch", "--show-current"], {
+      cwd: created.worktree.worktreePath,
+      stdio: "pipe",
+    })
+      .toString()
+      .trim(),
+  ).toBe("pas-101-slow-sidebar");
+});
+
 test("renames the branch from a github_pr attachment when no prompt is supplied", async () => {
   const { repoDir, tempDir } = createGitRepo();
   cleanupPaths.push(tempDir);

packages/server/src/server/paseo-worktree-service.ts

@@ -90,7 +90,7 @@ async function createPaseoWorktreeWithPriority(
         },
       });
     }
-    await maybeMarkFirstAgentBranchAutoNameEligible({ createdWorktree });
+    await maybeMarkFirstAgentBranchAutoNameEligible({ createdWorktree, input });
     const workspaceCwd = mapWorkspaceRelativeCwdToWorktree({
       relativeWorkspaceCwd: workspaceCwdPlan.relativeWorkspaceCwd,
       targetWorktreePath: createdWorktree.worktree.worktreePath,
@@ -280,11 +280,16 @@ async function findAvailableBranchName(options: {
 
 async function maybeMarkFirstAgentBranchAutoNameEligible(options: {
   createdWorktree: Awaited<ReturnType<typeof createWorktreeCore>>;
+  input: Pick<CreatePaseoWorktreeInput, "branchName">;
 }): Promise<void> {
-  const { createdWorktree } = options;
+  const { createdWorktree, input } = options;
   if (!createdWorktree.created || createdWorktree.intent.kind !== "branch-off") {
     return;
   }
+  // A branch the caller named is their choice; only a placeholder slug is replaced.
+  if (input.branchName !== undefined) {
+    return;
+  }
 
   await writePaseoWorktreeFirstAgentBranchAutoNameMetadata(createdWorktree.worktree.worktreePath, {
     placeholderBranchName: createdWorktree.worktree.branchName,