feat: Library surface + IPC-wired catalog

[johnnyhuy]

Summary

Two things in one PR:

1. Library surface — the 3-pane shell from the design system (rail · 7-harness list · INSTALL/REINSTALL/HEALTH inspector). This is the "chosen shell" from design.pen Layouts Lab.

2. Real IPC wiring — the Library's catalog now resolves through window.hoist.library.list() → IPC library:list → discoverAll(HARNESS_CATALOG), so the running app shows the harnesses actually installed on this machine (Claude Code 2.1.211, OpenCode 1.18.3, Codex CLI available) instead of the 7-row mock catalog.

What changed

src/renderer/App.tsx — new Rail component (56px icon-only nav), new LibrarySurface (filter pills · search · status-coloured list · main pane with model links + Configure/Open · "What you get" checklist), new LibraryInspectionPanel (right rail with 3 collapsible sections). Library is the default surface on app load.

src/main/providers/harnesses.ts — HARNESS_CATALOG extended with avatar, models, features, status per entry. Exports HarnessCatalogEntry type + findHarnessCatalog().

src/shared/channels.ts — new library:list channel.

src/main/ipc.ts — libraryList handler joins catalog entries with discoverAll() results. An entry is installed if the binary is on PATH, otherwise it falls back to its catalog status (e.g. available for Codex since we can't discover it).

src/preload/api.ts + src/preload/index.ts — window.hoist.library.list() returns LibraryEntry[]. LibraryEntry uses desc to match the catalog (cleaner than description).

src/renderer/styles/layout.css — .hoist-rail (56px), .hoist-body.is-rail grid, .hoist-library grid (header / toolbar / list / main), .hoist-library-row, .hoist-library-avatar, .hoist-library-main, .hoist-library-filters, .hoist-rail-kv, .hoist-terminal. ~375 lines added.

.gitignore — design.pen (binary, not for repo).

Verified

npm run typecheck   ✓
npm run lint        ✓
npm run catalog:check ✓
npm run test:extractor ✓
npm run build       ✓

The Library surface renders the actual installed harnesses on this machine: Claude Code 2.1.211, OpenCode 1.18.3, Codex CLI available. Right rail shows the INSTALL / REINSTALL / HEALTH sections with real KV data.

What didn't change

• The other 3 surfaces (Harnesses, Keys, Gateway) still use hardcoded data. They're already wired to their IPC channels (harness.discover, vault.list, gateway.list) but the renderer hasn't been switched yet — that's a follow-up.
• The 4 aspirational harnesses (Amp, Cursor, Aider, Cline) from the design mock don't ship in the catalog because there's no real installer discover for them. Adding them later means adding installMethods to the catalog entry.