fix(team-mode): skip tmux layout when opencode server unreachable

`createManagers` unconditionally called `markServerRunningInProcess()`
whenever `tmuxConfig.enabled` was true, which made `isServerRunning()`
short-circuit to `true` for *any* serverUrl — bypassing the guard in
`createTeamLayout` that is supposed to skip pane creation when the
opencode server is not running.

When a user launches vanilla `opencode` (no `opencode serve` /
`opencode web`), `ctx.serverUrl` is undefined and the TmuxSessionManager
falls back to `http://localhost:4096`. With the in-process flag set, the
team layout proceeded to spawn tmux panes whose `opencode attach`
commands then failed with "Unable to connect" — exactly the symptom in
the bug report.

Only mark the server as in-process running when the SDK actually
provides `ctx.serverUrl`. When it does not, `isServerRunning()` falls
back to a real HTTP probe, the existing guard in `createTeamLayout`
returns null, and no panes are created.

Closes #3894

src/create-managers.test.ts

@@ -175,6 +175,28 @@ describe("createManagers", () => {
     expect(markServerRunningInProcess).toHaveBeenCalledTimes(1)
   })
 
+  it("#given tmux is enabled but ctx.serverUrl is undefined #when managers are created #then it does NOT mark the server as running (issue #3894)", () => {
+    // Vanilla `opencode` (no `opencode serve` / `opencode web`) leaves
+    // ctx.serverUrl undefined. Marking the server as in-process running
+    // would short-circuit isServerRunning() in createTeamLayout, letting
+    // it spawn tmux panes whose `opencode attach` then fails because no
+    // server is actually listening on the fallback port.
+    const ctx = createContext("/tmp")
+    const ctxWithoutServerUrl = { ...ctx, serverUrl: undefined as unknown as URL }
+    const args = {
+      ctx: ctxWithoutServerUrl,
+      pluginConfig: OhMyOpenCodeConfigSchema.parse({}),
+      tmuxConfig: createTmuxConfig(true),
+      modelCacheState: createModelCacheState(),
+      backgroundNotificationHookEnabled: false,
+      deps: createDeps(),
+    }
+
+    createManagers(args)
+
+    expect(markServerRunningInProcess).not.toHaveBeenCalled()
+  })
+
   it("#given openclaw is enabled #when the background session-created callback runs #then it dispatches openclaw with the tracked pane id", async () => {
     const args = {
       ctx: createContext("/tmp/project"),

src/create-managers.ts

@@ -57,7 +57,15 @@ export function createManagers(args: {
   const { ctx, pluginConfig, tmuxConfig, modelCacheState, backgroundNotificationHookEnabled } = args
   const deps = { ...defaultCreateManagersDeps, ...args.deps }
 
-  if (tmuxConfig.enabled) {
+  // Only mark the server as in-process when the SDK actually exposes a
+  // serverUrl. `tmuxConfig.enabled` alone is not proof of a running server —
+  // a vanilla `opencode` session (no `opencode serve`/`opencode web`) leaves
+  // `ctx.serverUrl` undefined, and marking it running would make
+  // `isServerRunning` short-circuit to true. That bypasses the guard in
+  // `createTeamLayout` and lets it spawn tmux panes whose `opencode attach`
+  // command then fails because nothing is actually listening on the
+  // fallback port (issue #3894).
+  if (tmuxConfig.enabled && ctx.serverUrl) {
     deps.markServerRunningInProcessFn()
   }
   const tmuxSessionManager = new deps.TmuxSessionManagerClass(ctx, tmuxConfig)