Two gaps in 0.3.72/73, both of which left chunking looking enabled while doing
nothing useful.

THE THRESHOLD WAS A NUMBER SOMEONE TYPED.

    max_len = int(_emb_cfg.get('n_ctx') or _raw.get('n_ctx') or 8192)

Set n_ctx above what the model accepts and the windows are built too big; the
tokenizer then truncates each window at its real limit anyway and chunking
silently stops protecting anything -- the same invisible loss this code exists
to remove, reached through a config typo instead of a missing feature. The
window is now min(configured, tokenizer.model_max_length), with one trap
handled: HuggingFace sets model_max_length to a sentinel near 1e30 when the
checkpoint declares none, and believing that means never chunking at all, so a
value that large is read as "unknown" and the caller's number stands. Same clamp
on the sentence-transformers path, taking the smaller of max_seq_length and the
tokenizer's own limit.

THE MULTI-VECTOR PATH COLLECTED THE COUNTS AND DROPPED THEM. It builds its own
response, so the dense path's report did not cover it -- chunking was invisible
on exactly the path that needs it most, which is the bug this feature was
written to fix. It now reports

    "chunked": {"windows": [...], "pool": ..., "token_limit": N}

and logs the limit with the merges applied. `token_limit` is deliberate: it is
what makes a WRONG n_ctx visible rather than merely ineffective.

46 tests. Suite at the 25 pre-existing failures.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HXRMe9ZPUQCCCtBai9uqt3