Consolidate host styling patterns into unified documentation

Merge the separate "Support native host styling using CSS variables" and
"Reacting to light/dark theme changes" sections into a single "Matching
host styling (CSS variables, theme, and fonts)" pattern. This provides
clearer guidance by covering all three concerns together.

- Rename `docs/patterns.ts` to `docs/patterns.tsx` for JSX support
- Add `hostStylingVanillaJs` and `hostStylingReact` consolidated examples
- Enhance `applyHostFonts_fromHostContext` to apply initial fonts after
  `connect()`, not just on context change
- Add CSS usage examples to `applyHostStyleVariables()` JSDoc
- Update font example to use `var(--font-sans, system-ui, sans-serif)`

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tsconfig.json

@@ -15,6 +15,6 @@
     "skipLibCheck": true,
     "resolveJsonModule": true
   },
-  "include": ["src/**/*.ts", "src/**/*.tsx", "docs/**/*.ts"],
+  "include": ["src/**/*.ts", "src/**/*.tsx", "docs/**/*.ts", "docs/**/*.tsx"],
   "exclude": ["node_modules", "dist", "examples/**/*.ts"]
 }