Cap the hint prompt at 120 tokens: a full 223-token prompt garbles small models

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/Architecture.md

@@ -149,7 +149,7 @@ environment). See `WorkBreakdown.md` for the itemized checklist.)
 5. Worker runs the pipeline (chunked, with timestamps), streaming partial results
    back via `{type:"partial"}` messages; final result as `{type:"result"}`.
    A hint becomes `<|startofprev|> hint.` once per pass (`worker/prompt.ts`,
-   cut to Whisper's 223-token prompt budget at a whole word) and is prepended
+   cut to a 120-token prompt budget at a whole word) and is prepended
    to the decoder input of every 30 s window by a wrapper around the model's
    `generate()`, which also strips it from the output again (D-WS2a).
    Live passes (4.1b) carry the same `prompt`.