feat(welcome): recent projects on default canvas

[nullxnothing]

Redesigns the default canvas (empty-workspace welcome) with RECENT PROJECTS as the anchor (Variation A).

UI

• Lowercased daemon title; tagline now path · no file open.
• Fused 3-up action row (shared border, 1px hairline gaps): Open folder (⌘O) · Launch agent (green primary) · Clone repo.
• RECENT PROJECTS block: mono header + View all (N) →, bordered list with 46px clickable rows (folder · name · branch chip · path · last-opened · pin-on-hover; pinned = amber, sticky).
• Demoted START BUILDING strip (4-up compact chips) + keyboard hints.
• Tokens-only (CSS Modules + styles/tokens.css); controls use --radius-sm; no new literals.

Backend (schema V44 → V45)

• projects table gains pinned + branch columns (base table + V45 ALTER migration + idx_projects_pinned).
• projects:list orders pinned-first and refreshes/caches each project's git branch.
• New projects:setPinned IPC; pin toggles persist across reloads.

Tests / gates

• typecheck, build, lint:styles green.
• Added V45 migration test. Full suite: 585/586 (the 1 failure is the pre-existing, unrelated SeekerRelayService port test).