`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
PeterPonyu