fix(ui): align tab and segmented control geometry

[kev1n77]

Summary

Align TabGroup and SegmentedControl geometry and interaction surfaces with the design specifications.

• Use 30px compact tabs with 14px icons and 4px icon-to-label spacing.
• Use a borderless 36px medium segmented control with 30px segments, 3px insets, 4px gaps, and 12px horizontal segment padding.
• Apply compact tabs to settings pages and medium segmented controls to MiniApp category filters.
• Update Design Lab previews, pressed states, long-title examples, and component documentation.

Type and Areas

Type: Bug fix / UI/UX

Areas: Design tokens, shared UI components, Design Lab, Web UI settings, MiniApps

Motivation / Impact

Compact tabs previously retained oversized icons and spacing, while segmented controls used borders and internal dimensions that differed from the intended design.

This change gives settings navigation and MiniApp category filters consistent sizing and clearer interaction states. Standard tabs retain their existing 40px height, and the default small segmented control retains its 28px outer height.

Verification

• pnpm run design-system:check — passed.
• pnpm run check:web — passed, including theme audits and TypeScript checks.
• Visual review remains pending for the complete hover, pressed, focus, disabled, theme, density, and narrow-layout matrix.

Review entry points:

• Design Lab → TabGroup and SegmentedControl component pages.
• Design Lab → Patterns → scene toolbar and settings examples.
• Product → Settings tabs and MiniApp gallery/market category filters.

Reviewer Notes

• Commit: 521e15aa7.
• Changes are limited to presentation, tokens, previews, and component sizing at existing call sites.
• No backend protocol or persisted-data changes.
• Mobile touch geometry remains independently owned.
• Remote workspace, Remote control, Peer Device Mode, and Detached Dispatch were not exercised end to end.

Checklist

• This PR is focused and does not include secrets, temporary prompts, generated scratch files, or unrelated artifacts.
• Relevant verification is recorded above, or skipped checks are explained.
• User-facing strings, docs, and locales are updated where applicable.