[FEATURE]: worktree-based workspace switching with stash-based warp

[haxllo]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Add workspace-level worktree support to the core workspace system: CLI commands (opencode worktree create|list|remove|reset) and TUI dialog integration that lets users switch between working copies via git worktree without leaving their current session.

why it matters

working on multiple branches simultaneously is a common workflow. Previously, users had to either:

• Manually manage separate clones
• Use git worktree externally and relaunch opencode
• Stash/discard uncommitted work manually
  None of these preserve session continuity when switching context.

what i did

• CLI: opencode worktree create|list|remove|reset commands
• TUI: Warp dialog to switch between worktrees via stash-based git worktree
• Core: Optional directory field on workspace, VCS stash/stashPop endpoints
• UX: Status indicator, sidebar/footer worktree labels, auto-stash on leave + pop on return

Benefits

• Switch branches without leaving your opencode session
• No manual stash management auto stash on leave, auto-pop on return
• No separate clones needed leverages git worktree
• Workspace continuity: same project context, just different working tree

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: \--worktree\ / \-w\ CLI flag for git worktree isolation #35471: Similar feature request for worktree CLI integration (CLI commands for worktree create/list/remove/reset)
• [FEATURE]: Add workspace as a separate branch within the same project #35525: Very similar concept of switching between branches/worktrees within the same project session
• [FEATURE]: Configurable worktree creation — base ref, branch naming, repo-relative path #33332: Configurable worktree creation (base ref, branch naming, path) — closely related scope

Please review these issues and comment on how your request differs if it does.

[haxllo]

This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: --worktree\ / -w\ CLI flag for git worktree isolation #35471: Similar feature request for worktree CLI integration (CLI commands for worktree create/list/remove/reset)
• [FEATURE]: Add workspace as a separate branch within the same project #35525: Very similar concept of switching between branches/worktrees within the same project session
• [FEATURE]: Configurable worktree creation — base ref, branch naming, repo-relative path #33332: Configurable worktree creation (base ref, branch naming, path) — closely related scope

Please review these issues and comment on how your request differs if it does.

#35525 is the same high-level need (workspace on different branch). #36048 adds the specific implementation design (worktree CLI subcommands + stash-based warp). My PR #36052 implements it. #35471 (CLI flag) and #33332 (configurability) are complementary, different approaches or extensions Not a duplicate.

@jlongster