fix(ui): prevent text descender clipping in components and navigation

[kev1n77]

Summary

• Prevent text descender clipping in shared buttons, tabs, menus, cards, and navigation labels.
• Correct line heights in navigation, session rows, and skill lists.
• Allow session rows with assistant subtitles to grow with their content.
• Add regression tests for text truncation and bundled font metrics.

Type and Areas

Type: Bug fix / UI/UX / test

Areas: Shared UI component library, web UI navigation, skills

Motivation / Impact

Tight line heights combined with overflow clipping cut off the lower parts of letters such as g, y, p, and q.

Affected text slots now use the existing base line-height token while preserving font sizes, weights, horizontal ellipsis, and the two-line skill description limit.

Verification

Completed during implementation:

• pnpm run check:web — passed.
• pnpm run design-system:check — passed, including 174 UI tests and 52 Design Lab tests.
• node --test design-system/packages/ui/tests/text-clipping.test.mjs — 10 tests passed.
• git diff --check — passed.

Manual visual verification and remote-scenario testing were not performed.

Reviewer Notes

• Includes only commits 333868481 and dce49f064.
• Excludes the previously merged mini app tag layout fix.
• No font assets, global typography token values, persisted data, or API contracts changed.
• Single-line session rows retain their existing height; rows with assistant subtitles can grow.
• Please review text descenders at different font sizes and display scales.

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.