Cmd+K: fix Recent Files flicker

[Sushants-Git]

Fixes #889: Cmd+K now opens with Recent Files already drawn, so the menu no longer flickers.

Why

Before every workspace-file request, resolve_target checks the chat's folder. That check ran 6 git processes one after another (~37 ms). The search itself takes ~0.3 ms, so Recent Files arrived a frame or two after the palette was drawn.

Fix

• workspace_checkout: one git worktree list instead of refs(), which ran 4 commands to read one column. This also accepts detached worktrees, which the old code rejected.
• checkout_identity: one git rev-parse call instead of two.
• resolve_target: for chat targets, the two calls run concurrently. A request-supplied checkoutPath is still checked before git runs in it.

Request round trip: ~45 ms → ~5–8 ms.

Screen.Recording.2026-10-13.at.3.42.05.PM.mov

Testing

• cargo test -p zeron-engine --lib passes, plus a new test that every worktree is accepted, including detached ones (fails on the old code).
• Checked live on macOS.

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[wingleeio]

Thanks! Resolving the checkout identity in one rev-parse and alongside the authorization check removes the serialized git round-trips, and listing worktrees straight from git worktree list also accepts detached worktrees, which refs() missed. Nice test.

I pushed one commit (53ed0d3): worktree_paths now parses --porcelain -z, so a worktree whose path contains a newline can't inject an extra worktree <path> entry into the accepted checkouts (falls back to the newline form on Git < 2.36). The test covers it.

Ran cargo check -p zeron-engine --all-targets, the engine lib suite, and --test workspace_files merged with main — green.