New display themes (E-Ink & CRT) and a simpler Appearance page

[DevMando]

Summary

Adds two new reading-focused display themes and reorganizes the theme/appearance settings so they're easier to navigate. This is a UI/personalization enhancement only — no changes to chat, model behavior, or data handling.

What's shipping

Two new themes (the existing 13 are unchanged):

• E-Ink Paper — a warm paper-and-black-ink, grayscale look that reads like a Kindle. Motion is removed, the optional chat-background image is rendered as a dithered "e-ink" picture, and emoji are desaturated so the whole page reads as ink on paper.
• Cathode Ray (CRT) — a deep-black retro "picture tube" look with glowing text and scanlines. Named after the display technology rather than any TV brand, to avoid trademark exposure.

Redesigned Appearance page — the previous collapsible dropdown cards are replaced by a two-pane layout: the theme list is always visible on the left, and Chat Background + Window Opacity are always open on the right. Everything is on screen at once, so it takes fewer clicks to find and change a setting.

Why

Users asked for more comfortable, personalized reading options (reduced eye strain, a fun retro mode) and a settings page that's quicker to navigate.

Risk / scope

• Low risk. Purely cosmetic and opt-in — nothing changes unless a user selects a new theme.
• Performance-safe by design. Both new themes use static rendering only (no animation/flicker loops), which avoids a known CPU-usage pitfall in the chat view.
• Isolated. New visual effects are gated to their own themes and cannot affect the other 13.
• No new third-party dependencies; changes are self-contained in the desktop app.

Verification

• Builds clean (0 warnings, 0 errors).
• Existing themes, chat background, and window-opacity controls all continue to work; only their layout on the settings page moved.

Reviewer notes

• Worth a quick visual check on a narrow window: the two-pane layout wants ~750px of width before the right pane scrolls. A stacked/responsive fallback can be added later if needed.