v0.1.27 — mistral-large-3 coder panel (262K advertised window) + canonical [DONE] framing

Follow-up release to v0.1.26: both changes came out of cross-provider post-release reviews of that release.

Changed

• fusion-coder panel: gpt-oss:120b → mistral-large-3:675b. gpt-oss (131K ctx) capped the advertised fusion-agents/fusion-coder context window at 131K while every other member has ≥262K — the advertised window is now 262144 (the kimi bound). Selected against the live Ollama Cloud roster with four filters: ctx ≥ 262K; Western lineage (the panel keeps its 2-Chinese-labs + 1-Western decorrelation — Mistral); accepts foreign tool-call history (panel-shaped probe: 200 in 7 s, correct minimal-fix answer; gemini-3-flash still 400s on thought_signature); deliberation calibre (675B MoE). Rejected: nemotron-3-super (120 s probe timeout), gemma4:31b (calibre); runner-up: devstral-2:123b. fusion-researcher intentionally keeps gpt-oss. Honest open item from the review: the quality delta vs gpt-oss stays unmeasured until the fusion-lift bench is re-run — bounded meanwhile (one voice of three, weighed by the judge; the synth writes the final code). Preset tables (README en/ua/ru) and the example config synced, including the example's stale pre-v0.1.23 kimi synth.

Fixed

• Tool-turn guard emits canonical single-[DONE] framing. When the upstream ended its stream with [DONE] but no finish_reason chunk, the guard forwarded that [DONE] and then appended its own after the terminal-less recovery. Production clients were shielded by the downstream usage-injection transform, so no corruption was observable — but the guard's own output must be canonical regardless of what sits behind it. The upstream [DONE] is now swallowed; every finish branch appends its own. +1 framing test (307 total, green).