fix: solve #4384 — guard Cmd+T / new terminal against rapid presses during daemon bootstrap

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Root cause

On cold start, the first terminal.createSession blocks for up to ~5s waiting for the pty daemon to come up (see DaemonSupervisor.waitForSocket(socketPath, 5_000)). Every additional Cmd+T press or "New Terminal" click during that window awaits the same bootstrapPromise. When the socket becomes ready, all queued tRPC calls unblock together and each one creates a terminal — so 5 mashed Cmd+T's during cold start spawn 5 terminals at once.

The two unguarded handlers identified in #4384:

• useWorkspaceHotkeys.ts NEW_GROUP (Cmd+T)
• useWorkspacePaneOpeners.ts addTerminalTab (sidebar/menu "New Terminal")

The fix

Mirror the existing isClosingPaneRef pattern used by CLOSE_PANE: drop re-entrant calls while a creation is pending. Extracted as a tiny createInFlightGuard factory next to useV2TerminalLauncher so the lock state is held in a useRef per handler and the logic is unit-testable.

This is fix #2 from the issue's "Proposed fixes" list. Fixes #1 (eager bootstrap) and #3 (optimistic placeholder) are not addressed here.

Tests

• inFlightGuard.test.ts includes a reproduction test that simulates rapid presses landing on a single deferred bootstrap — without the guard 5 presses produce 5 terminals; with the guard, 1.
• Also covers lock release on success and on rejection.

bun test src/renderer/routes/_authenticated/_dashboard/v2-workspace/\$workspaceId/hooks/useV2TerminalLauncher/inFlightGuard.test.ts
✓ 4 pass / 0 fail

Typecheck (bun run typecheck in apps/desktop) and bun run lint are clean.

Out of scope

Other launcher consumers (SPLIT_AUTO, SPLIT_RIGHT, SPLIT_DOWN) are not guarded — those aren't typically mashed during cold start and the issue scopes the fix to the two cmd+T paths. Easy to extend if the same concern surfaces for splits.

Closes #4384

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Summary by cubic

Prevents multiple terminals from spawning on cold start by dropping re-entrant Cmd+T and “New Terminal” requests while the daemon bootstrap is in-flight. Fixes #4384.

• Bug Fixes
  • Added createInFlightGuard and wired it into NEW_GROUP and addTerminalTab to coalesce rapid presses into a single terminal creation.
  • Added unit tests to reproduce Desktop: Cmd+T / new terminal blocks on first open, then buffered clicks fire at once #4384 and verify lock release on success and failure.

^{Written for commit 582e08b. Summary will update on new commits.}