Var-ify inline styles and snap off-scale type/radii (design Phase 2)

Phase 2 of the design-contract cleanup:
- 346 inline-style hexes (+7 #475569, mapped by property) -> var(--token),
  scoped to CSS-value position so JS-logic/quoted hex, the meta theme-color,
  SVG attrs, and the no-:root share-export region stay literal; #fff and
  no-token hexes left as-is.
- Snap off-scale font sizes (9/10.5->10, 11.5/12.5->12, 15->16, 24->22) and
  radii (3->4, 5->6, 7->6, 11->12, 9->8|10) to the scale.
- Bump to 0.2.161, which also ships the previously-uninstalled 0.2.160
  share-page HTML export.

startos/versions/v0.2.161.ts

@@ -0,0 +1,12 @@
+import { VersionInfo } from '@start9labs/start-sdk'
+
+export const v_0_2_161 = VersionInfo.of({
+  version: '0.2.161:0',
+  releaseNotes: {
+    en_US: 'New: shareable HTML export for YouTube recaps — a self-contained .html file with the embedded video and expandable timestamped summaries baked in, openable by anyone with no account (native share sheet on mobile, download on desktop). Plus a design-system pass: colors, type sizes, and corner radii now follow one consistent set of tokens across the app.',
+  },
+  migrations: {
+    up: async ({ effects }) => {},
+    down: async ({ effects }) => {},
+  },
+})