fix(tui): only offer a new directory when the location is missing - #57532

Issue for this PR

Closes #55250

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

The TUI replaced the composer with the blocking "Session location unavailable — Choose another directory to continue this session." prompt after any failed location sync, even when the folder was still there.

LocationProvider.sync (packages/tui/src/context/location.tsx) set the location error on every sync rejection. The sync fans out to a dozen catalog endpoints under one Promise.all (packages/client/src/solid/data.ts, location.sync), so one transient failure fails the whole sync. Under load the server answers GET /api/model with 503 ServiceUnavailableError: Location plugins did not finish activating (the 5s awaitPlugins budget in packages/server/src/location.ts), the sync rejects, and the TUI claims the directory is gone and offers to move the session somewhere else.

Only the server's typed LocationNotFoundError proves the folder is missing. The web client already gates on it (packages/app/src/workspaces/location.tsx); the TUI did not.

This change:

• splits the location state into missing (the server's LocationNotFoundError) and error (anything else), so only a genuinely missing directory mounts the recovery prompt;
• retries a failed sync with backoff, so a transient failure heals on its own instead of leaving the session without its catalog;
• compares the missing directory with sameDirectory, so a Windows path that differs only in case still matches;
• drops a duplicated location read that made every failed sync ask the server twice.

A transient failure stays visible as location.error instead of being swallowed.

How did you verify your code works?

• packages/tui/test/session-location-unavailable.test.tsx drives the real app: a transient /api/model 503 is retried and the composer stays usable, a persistent 503 keeps the composer usable, and a LocationNotFoundError still shows the recovery prompt. Reverting the source change fails the first two and reproduces the reported screen verbatim.
• packages/tui/test/cli/tui/location-provider.test.tsx: a missing location is asked exactly once (retrying cannot succeed until the folder changes), while any other failure is retried and lands in error, never in missing.
• cd packages/tui && bun test --timeout 60000 test/session-location-unavailable.test.tsx test/cli/tui/location-provider.test.tsx test/cli/tui/prompt-move.test.tsx test/cli/tui/data.test.tsx test/context/session-tabs.test.tsx test/component/session-tabs-status.test.tsx test/session-dialog-resync.test.tsx -> 103 pass / 0 fail. With the source change reverted: 99 pass / 4 fail (the four new cases; no other test changes state).
• bun run typecheck and oxlint are clean.

Screenshots / recordings

No visual change for a genuinely missing folder. The recovery prompt no longer appears for a folder that is present.

Related

• Covers the fix in fix(tui): only flag session location missing on LocationNotFoundError #55940 (classify the failure) and fix(tui): tolerate transient failures in the post-reconnect location sync #55258 (retry the sync). fix(tui): tolerate transient failures in the post-reconnect location sync #55258's stated limitation — "a location that stays unreachable past the retry window (~1.5s) still surfaces the recovery prompt" — does not apply here, because the retry budget classifies the failure instead of assuming it.
• The server-side cause of the transient failures is the hard-coded 5s plugin activation budget in packages/server/src/location.ts, which is a separate change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR