v0.3.17

An explicit --tokenizer that cannot be loaded now stops the proxy at startup (#32, #33).

Before, if --tokenizer was given but the optional tokenizers package was missing from the proxy's environment (or the file was invalid), the proxy silently fell back to the chars/3.5 estimate. The window guard then worked on an estimate while you believed it was exact; in one benchmark run the estimate was 2,484 tokens (9%) short and the request asked for 897 tokens more than the window allowed (the engine trimmed it with fit_max_tokens).

• Now startup fails with the original cause and the fix: pip install "mnemonic-proxy[exact]" in the same interpreter, or drop --tokenizer to run on the estimate deliberately.
• Running without --tokenizer is unchanged (estimated, as before).

If you install with plain pip install mnemonic-proxy and pass --tokenizer, install the [exact] extra before upgrading.