v8.17.4 — #239 prewarm the Meet forced-delegation fallback line (PR #244, bump PR #245)

v8.17.4 — #239 TTS cache prewarm: include the Meet forced-delegation fallback line (PR #244, squash d49f65a; bump PR #245). collectFixedTtsPhrases now lists forcedDelegationFallbackMeet when the provider is OpenClaw-routed, llm.firstTokenDelegateMs > 0 and gatewayEvents.enabled is on — the same gate under which the pipeline speaks it — so the line is prewarmed at startup and kept by the v8.17.2 orphan prune instead of being synthesised live on every forced-delegation timeout and deleted at every next start. Flag-off phrase list byte-identical to v8.17.3. No new setting, no docs change. Evidence: PR #244 completion record (host make test on b37c551 99/99, 3 seats Opus/Qwen/Gemini r1 3/3 GO, blocking 0, no delta; Opus hashed prewarm key == speak key), main make test on d49f65a 99/99 1104 pass, CI runs 34335971816 / 34369439361. Between v8.17.3 and this tag: #244, #245 (bump), repo-state pins (non-shipping).