refactor(replay): simplify file tree rows

[beruro]

Summary

• remove chronological sequence/path metadata from narrow Session Replay file rows
• delete the now-unused file-operation sequence model and tests
• preserve canonical file names, icons, write-status badges, hierarchy, and selection behavior
• source sticky-directory background styling from the active primary Sidebar surface token

Validation

• focused Session Replay Vitest suite: 13 passed
• pnpm exec tsc --noEmit --pretty false
• Prettier and ESLint on all changed TypeScript/TSX files
• git diff --check

Frontend UI audit

2 fixes applied, 4 patterns kept with documented reasons, 0 remaining abstraction candidates. The report is included at docs/frontend-ui-audit-2026-07-24/SessionReplayFileTree.md.

Architecture audit

Covered compilation, dead-reference removal, presentation ownership, naming, and type-surface cleanup. No wire protocol, initialization, resolver, or background lifecycle behavior changes.

[Harry19081]

Already done