* feat: add all Draw.io themes to settings panel
Add all available Draw.io themes (kennedy, atlas, dark, min, sketch, simple)
to the settings panel dropdown. Previously only min and sketch were available
as a toggle button.
Changes:
- Replace the Draw.io style toggle button with a dropdown selector
- Expand theme type from "min" | "sketch" to include all 6 themes
- Update localStorage validation to accept all themes
- Update handler from toggle to direct theme selection
Closes#499
* fix: localize theme labels, tighten DrawioTheme typing, sync dark param
- Move DRAWIO_THEMES + DrawioTheme to lib/drawio-themes.ts; reuse in
page.tsx, chat-panel.tsx and settings-dialog.tsx instead of `string`
- Localize theme dropdown labels (Dark/Minimal/Sketch/Simple) in
en/zh/ja/zh-Hant; keep proper-noun themes (Kennedy/Atlas) as-is
- Drop trailing colon from drawioStyleDescription and remove dead
switchTo/minimal/sketch keys in all 4 dictionaries
- Auto-sync drawio dark URL param when ui="dark" is selected
- Add aria-label to drawio-style SelectTrigger
* fix: use kennedy as default theme and label it "Default"
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Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>
