fix(maestro): default the worktree toggle off when the directory is itself a worktree (#91)

Picking a project row that is itself a linked git worktree used to
default 'Create git worktree' on, so spawning asked for a second
worktree of an already-checked-out branch and git refused. Both clients
now default the toggle off there: the session just runs in that existing
worktree with no worktree record (not adoption). Turning it back on by
hand still tries, per the issue's non-goal.

crates/maestro-tui/src/draft.rs

@@ -654,6 +654,11 @@ impl DraftPane {
             let project = visible[sel].project.clone();
             self.picked_cwd = Some(project.path.clone());
             self.cwd_raw_visible = false;
+            // A directory that *is* a linked worktree defaults to spawning in
+            // place (#91): creating a second worktree of its branch fails.
+            // Turning it back on by hand still tries (git's own message),
+            // which is deliberate (#91 non-goal).
+            self.worktree_enabled = !project.is_worktree;
             // The scan already knows this directory's repo (#61): no probe
             // round trip needed, exactly like the web form.
             let repo = project
@@ -1689,6 +1694,40 @@ mod tests {
         assert!(wt.create_branch);
     }
 
+    #[test]
+    fn picking_a_worktree_project_defaults_the_toggle_off() {
+        let mut draft = DraftPane::default();
+        let mut wt = repo_project("wt-91", "/repos/wt91", "/repos/main", 1, None);
+        wt.is_worktree = true;
+        draft.set_projects(
+            vec![
+                repo_project("main", "/repos/main", "/repos/main", 2, None),
+                wt,
+            ],
+            Utc::now(),
+        );
+        draft.focused_field = DraftField::DirPicker;
+        typed(&mut draft, "wt-91");
+        draft.on_input(&InputKey::Enter);
+
+        assert!(
+            !draft.worktree_enabled,
+            "the directory is already a worktree; spawning in place"
+        );
+        assert!(
+            draft.build_request().unwrap().worktree.is_none(),
+            "no worktree record — the session just runs there (#91)"
+        );
+
+        // Deliberately re-enabling still works, and the scan-known base repo
+        // survives so the toggle-on path needs no new probe.
+        draft.focused_field = DraftField::WorktreeToggle;
+        draft.on_input(&InputKey::Enter);
+        assert!(draft.worktree_enabled);
+        assert_eq!(draft.base_repo.as_deref(), Some(Path::new("/repos/main")));
+        assert!(draft.take_gitroot_probe().is_none());
+    }
+
     #[test]
     fn raw_path_targets_probe_gitroot_and_resolution_feeds_the_spec() {
         let mut draft = DraftPane {

web/src/spawnForm.ts

@@ -430,9 +430,19 @@ export function createSpawnForm(opts: SpawnFormOptions): SpawnFormHandle {
     cwdRawWrap.hidden = true;
     markActiveProject(project.path);
     // The scan already knows this directory is inside a repo (#61): the
-    // toggle defaults back on and no /api/gitroot round trip is needed.
+    // toggle defaults back on and no /api/gitroot round trip is needed —
-    wtEnabled.checked = true;
+    // unless the directory *is* a linked worktree itself (#91): spawning
-    applyProjectRepo(project.base_repo ?? project.path);
+    // in place is the only thing that works there, so default the toggle
+    // off. Turning it back on by hand still tries (and fails with git's
+    // own message), which is deliberate (#91 non-goal).
+    wtEnabled.checked = !project.is_worktree;
+    if (project.is_worktree) {
+      inferredBaseRepo = null;
+      wtBody.hidden = true;
+      wtHint.hidden = true;
+    } else {
+      applyProjectRepo(project.base_repo ?? project.path);
+    }
     emit();
     // Picking a project pre-selects the command it was last used with.
     const match = presets.find((p) => p.command === project.last_command && p.command !== "");

web/src/spawnFormWorktree.test.ts

@@ -18,6 +18,7 @@ const BRANCHES = [
  * its branch list is still in flight. */
 function stubFetch(opts?: {
   gateBranches?: (release: () => void) => void;
+  projects?: unknown[];
 }): string[] {
   const urls: string[] = [];
   const gated = new Promise<void>((resolve) => {
@@ -37,7 +38,7 @@ function stubFetch(opts?: {
         return new Response(JSON.stringify(BRANCHES), { status: 200 });
       }
       if (url.includes("/api/projects")) {
-        return new Response(JSON.stringify(PROJECTS), { status: 200 });
+        return new Response(JSON.stringify(opts?.projects ?? PROJECTS), { status: 200 });
       }
       return new Response(
         JSON.stringify({ hostname: "h", version: "0", home_dir: "/home/user", presets: [] }),
@@ -100,6 +101,34 @@ describe("spawnForm worktree defaults and branch picker (#61)", () => {
     );
   });
 
+  it("defaults the worktree toggle off for a row that is itself a worktree (#91)", async () => {
+    urls = stubFetch({
+      projects: [
+        {
+          path: "/home/user/wt-91",
+          name: "wt-91",
+          is_worktree: true,
+          base_repo: "/home/user/maestro",
+          last_activity: "2026-08-20T10:00:00Z",
+        },
+      ],
+    });
+    handle = createSpawnForm({ onSuccess() {} });
+    document.body.appendChild(handle.el);
+    for (let i = 0; i < 40; i++) await Promise.resolve();
+
+    handle.el
+      .querySelectorAll<HTMLButtonElement>(".project-row")
+      .forEach((row) => row.dataset.cwd === "/home/user/wt-91" && row.click());
+    await drain();
+
+    expect(handle.el.querySelector<HTMLInputElement>("input[name=worktree_enabled]")!.checked).toBe(
+      false,
+    );
+    expect(urls.some((u) => u.includes("/api/gitroot"))).toBe(false);
+    expect(handle.el.querySelector<HTMLElement>(".wt-body")!.hidden).toBe(true);
+  });
+
   it("still probes the gitroot for a free-text directory", async () => {
     const form = await mount();