feat(worktrees): fetch remote source branch before worktree creation (#3296)

* feat(worktrees): fetch remote source branch before worktree creation

New worktrees based on a local branch that is behind its upstream now
fetch first and branch from the remote-tracking ref, so they are not
born stale. A global setting (on by default) in Settings > Behavior
controls this, and fetch failures toast a warning and fall back to
local state instead of blocking creation.

* fix(worktrees): wire fetch-source toggle to store and honor failed runtime fetches

The Behavior toggle only persisted the setting; the consumer reads the
config store at creation time, so a just-toggled-off setting kept
fetching until the next hydration. Update the store optimistically on
toggle and on page load, and roll it back when the save fails.

The VS Code runtime bridge resolves git fetches with { success: false }
instead of throwing, which the consumer read as success and silently
based the worktree on the stale remote ref. Treat any non-success
result as a failed fetch: warn and fall back to local state, matching
the web/desktop/mobile path.

* fix(worktrees): stop new remote-based worktrees from tracking the base branch

Creating a worktree with a remote start ref made git auto-track the
base branch (branch.autoSetupMerge), so with the new remote fetch every
behind-root worktree was born with upstream origin/<base> and plain
git push refused under push.default=simple.

The new branch's own upstream does not exist until its first push, and
the bootstrap deliberately refuses to write tracking config for refs
that were never fetched, so --set-upstream-to cannot re-point it.
Suppress the auto-track with --no-track on new-mode creation from a
remote ref: the branch ships with no upstream, matching the behavior
before the remote fetch until the first push sets it. Explicit
upstream keys now also win over the remote start ref inference,
aligning the create path with the validate path and the VS Code
runtime.

* fix(worktrees): keep the pre-create remote ref refresh soft

The client fetch and the server's pre-create fetchRemoteBranchRef both
refresh the same branch, and the second fetch throws on failure — so a
connection dropped between the two turned the promised soft fallback
into a rejected creation even though the remote-tracking ref was
already available locally.

The refresh is now best-effort when the ref exists locally (creation
proceeds from it) and still mandatory when the ref was never fetched,
preserving the materialization behavior for remote-only branches.
Applied to both the web server and the VS Code runtime.

* chore: ignore the .openchamber app runtime state directory

packages/ui/src/lib/i18n/messages/ko.settings.ts

@@ -575,6 +575,10 @@ export const settingsDict = {
   'settings.behavior.page.systemPromptOptimization.enable': '시스템 프롬프트 크기 최적화',
   'settings.behavior.page.systemPromptOptimization.enableAria': 'OpenCode 시스템 프롬프트 크기 최적화',
   'settings.behavior.page.systemPromptOptimization.info': 'build 및 plan 에이전트의 시스템 프롬프트를 약 40% 줄입니다. 다른 에이전트는 변경되지 않습니다. build 또는 plan을 재정의하는 사용자 지정 정의가 제거될 수 있으므로 이러한 워크플로에서는 활성화하지 마세요. OpenCode를 다시 시작하면 변경 사항이 적용됩니다.',
+  'settings.behavior.page.section.worktrees': '워크트리',
+  'settings.behavior.page.worktreeFetchSource.enable': '워크트리를 만들기 전에 원격에서 가져오기',
+  'settings.behavior.page.worktreeFetchSource.enableAria': '워크트리를 만들기 전에 원격에서 변경 사항 가져오기',
+  'settings.behavior.page.worktreeFetchSource.info': '새 워크트리는 로컬 체크아웃 대신 현재 브랜치의 원격 상태를 가져와서 만들어지므로 최신 상태를 유지합니다. 원격에 접근할 수 없으면 로컬 상태로 만듭니다.',
   'settings.behavior.page.systemPromptOptimization.restarting': '시스템 프롬프트 최적화를 적용하기 위해 OpenCode를 다시 시작하는 중…',
   'settings.behavior.page.field.systemPromptPlaceholder': '당신은 유용한 AI 어시스턴트입니다...\n\n모든 세션과 공급자에서 AI가 어떻게 행동해야 하는지에 대한 절대적인 규칙을 정의할 수 있습니다.',
   'settings.behavior.page.section.responseStyle': '응답 스타일',