feat(queue): deliver follow-ups at safe tool boundaries

[Mjones13]

Queued follow-ups currently wait for the entire active turn. This change delivers compatible owner messages after a successful native foreground tool boundary, once all observed parallel foreground tools finish. Delivery is server-owned, so leaving the thread view or disconnecting the client does not strand queued messages.

Automatic delivery reuses persisted promotion receipts and the effect outbox without interrupting or restarting tools. Receipt-sequence predecessor checks preserve the selected queue order through timestamp ties and delayed retries; failed, cancelled, uncertain, or invalidly recorded predecessors hold later deliveries. Approvals, held queues, unsupported steering, changed settings, and maintenance commands retain their existing hold or next-turn behavior. Web/mobile wording and composer documentation describe the new behavior.

Depends on #91 at 09ead6ea565ffce428e9cda1bd5696c69ce9e616; targets work/audit-stack-integration-20261004. This is a source-only handoff, with no deployment performed.

Validation:

• 144 affected tests passed. The same 45 failing test names reproduce on the untouched integration base; no new failures.
• Frozen-clock SQL tests reproduce the original lexical ordering bug and prove FIFO claims, delayed retries, failure/hold handling, receipt validation, and target isolation. A runtime test claims 12 reordered messages in the selected order.
• Claim and wake-up query plans use the existing predecessor index; no migration.
• Typecheck retains 933 errors with the same file/error-code counts as the base. FIFO-file lint passes; broader touched-file lint retains an unchanged node:crypto namespace-import violation.
• No native-provider, browser, device, screenshot, or timing-video verification was performed. Quiescence is observed rather than an atomic provider pause; this does not claim exactly-once native delivery.

The repository commit hook reformatted touched files. Pre/post-hook syntax comparisons verified those formatting changes were equivalent.

Implemented through the Codex harness with GPT-6.1 Sol; the FIFO design follows owner-requested GPT-6 Astra Extra High guidance.

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