v0.4.0: Laya only, offline, new header

LUAR now runs on Laya alone, works offline once installed, and has a simpler, neutral interface.

Breaking changes

• LM Studio removed. Laya is the only engine. The CLI options -e/--engine, --model and --lmstudio-url are gone.
• Laya is a required dependency. pip install luar installs it (and PyTorch, about 1 GB more than before); pip install "luar[all]" adds the web interface. luar[laya] still works and is now the same as plain luar.

New

• Works offline once installed. No telemetry, README screenshots served locally, and Laya loads from the local cache instead of checking the Hub on every run.
• luar download fetches the multilingual and English models up front (about 1.5 GB), so later runs never need the internet.
• Header buttons: README opens the manual (Português / English) in a side panel; Sample CSV downloads 20 made-up customer messages with expected_ answers to try LUAR right away.
• Neutral slate theme with no purple; the web interface runs Laya only.

Fixes

• score questions now send each level's description to Laya (they were dropped before), and the answer is the level label, not the full text.

Manual (English and Portuguese)

• New FAQ: Laya needs no training and does not learn from your data or corrections.
• Stronger score advice, with an urgency example that the model could not measure, and choice/noul alternatives.
• Section 8 is now "How accurate is Laya"; screenshots retaken from the current interface.