- Move `import html` to module top (was inside function body)
- Fix IndexError crash in /login when bot_name is empty string;
use `or 'Hermes'` fallback instead of .get() default which
doesn't guard against stored empty string
- Add server-side sanitization in POST /api/settings: strip + default
empty/whitespace bot_name to 'Hermes' before persisting
- Escape _bn initial char in ui.js innerHTML (esc() consistency)
- Add maxlength=64 to #settingsBotName input field
- Add tests/test_sprint27.py: 9 tests covering API round-trip,
empty/whitespace defaults, login page rendering, and XSS escaping
