Add compact list view toggle to email search results

[sanxiago]

Summary

• Search results currently render as detailed cards with highlighted body/attachment match snippets, which gets noisy when a query returns many hits.
• Adds a view toggle ("Detailed" / "List") on the search page. List view (the default) renders a compact table with just Subject, From, To, and Date for each hit, linking through to the archived email like the existing card view. Detailed view keeps the original card layout with match snippets.
• No backend or API changes — the search response already includes the fields needed for the compact view.

Test plan

• pnpm run check in packages/frontend — no new type errors (one pre-existing, unrelated error remains on dashboard/settings/system)
• pnpm run build in packages/frontend — production build succeeds, search page bundle compiles
• Manually verified against a local instance built from this branch, connected to real Postgres/Meilisearch data (read-only, no background workers) — confirmed the toggle renders, list view shows Subject/From/To/Date, switching views works, and rows link through to the archived email detail page.

🤖 Generated with Claude Code

[github-actions]

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[sanxiago]

I have read the CLA Document and I hereby sign the CLA

[sanxiago]

recheck