[codex] Improve search match highlighting

[jlitola]

Summary

Improves terminal search readability by separating header/path styling from search-match styling.

• adds a yellow match-highlight style for backend-provided title and summary spans
• keeps result targets and path headers cyan while highlighting matching query terms inside path segments
• carries the backend query through search_status result payloads so async/follow-up output gets the same location highlighting
• treats quoted query phrases as phrase terms for location highlighting, and prioritizes longer overlapping terms deliberately
• updates grep/search formatter tests for the shared match-span color
• fixes a minor optional-chain lint finding surfaced during validation

Why

Search output could match on file paths, but path matches were visually lost because both the header and highlight spans used the same cyan style. Yellow match spans make the actual matched term visible while preserving the existing header hierarchy.

Review Notes

Claude review cleanup addressed:

• fixed the immediate-search vs search_status highlighting asymmetry by threading result.query.raw through status payloads
• made length sorting observable by using longer-term priority when overlapping ranges compete
• documented and implemented quoted-phrase behavior so quoted phrases do not degrade into scattered path word highlights
• kept the optional-chain cleanup as the existing lint cleanup; the pushed history was not rewritten after PR creation

Validation

• bun test
• bun run typecheck
• bun run format:check
• bun run lint
• bun run build
• bun run smoke:cli
• bun run smoke:mcp