Deepen TDS integration: full terminal CSS coverage + 3 new backgrounds

Terminal Mode:
- Text selection: orange highlight rgba(255,107,0,0.28)
- Links: cyan (#00D4FF) with orange hover glow (#FF6B00)
- Code/pre: TDS green (#00FF88) on terminal bg, left green border
- Strong/b → orange, em/i → cyan, mark → amber, del → red
- Blockquote: orange left border (matches chat reply quotes)
- HR: cyan border with dim glow
- Input/textarea/[contenteditable] focus: orange glow ring
- Tables: TDS headers (orange+uppercase), cyan borders, hover rows
- List markers: cyan ▸ for ul, orange for ol
- Boot box-drawing alignment fixed (51→52 ═)
- data-theme=\"dark\" set on html element when terminal active
- Updated description: correct TDS palette names
- ▶ Boot replay button in settings (visible when terminal on)

Chat backgrounds (+3):
- Tactical: LotusGuild TDS exact cyan dot-grid (28px)
- Circuit: green grid + node dots on dark terminal bg
- Hex Grid: isometric cyan hexagonal outlines

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/state/settings.ts

@@ -3,7 +3,7 @@ import { atom } from 'jotai';
 const STORAGE_KEY = 'settings';
 export type DateFormat = 'D MMM YYYY' | 'DD/MM/YYYY' | 'MM/DD/YYYY' | 'YYYY/MM/DD' | '';
 export type MessageSpacing = '0' | '100' | '200' | '300' | '400' | '500';
-export type ChatBackground = 'none' | 'blueprint' | 'carbon' | 'stars' | 'topographic' | 'herringbone' | 'crosshatch' | 'chevron' | 'polka' | 'triangles' | 'plaid';
+export type ChatBackground = 'none' | 'blueprint' | 'carbon' | 'stars' | 'topographic' | 'herringbone' | 'crosshatch' | 'chevron' | 'polka' | 'triangles' | 'plaid' | 'tactical' | 'circuit' | 'hexgrid';
 export enum MessageLayout {
   Modern = 0,
   Compact = 1,