Implement CHUNK #2: server layer, core schemas/adapters, contract tests, seed

Complete the server-backed storage layer for PubScript so the app can run
against a real Fastify + SQLite backend instead of only local IndexedDB.

Server (@pubscript/server):
- db.ts: better-sqlite3 schema + migrations (users, shares, projects, books,
  chapters, entities, boards, ai_sessions, audit); WAL mode; idempotent
  admin bootstrap via PUBSCRIPT_ADMIN_EMAIL/PASSWORD.
- auth.ts: argon2 hashing, JWT-ish session tokens, guards, auth routes.
- routes.ts: REST CRUD for projects/books/chapters/entities/boards/ai_sessions
  with multi-tenant isolation and optimistic concurrency (baseRev).
- ws.ts: Fastify websocket hub for autosave + presence events.
- mapping.ts: row <-> core type conversion.

Core (@pubscript/core):
- Zod domain schemas (projects, books, chapters, entities, boards, ai_sessions)
  exported from index.
- storage-local.ts (IndexedDB/Dexie) and storage-server.ts (REST) adapters
  implementing the StorageAdapter contract.

Tests & tooling:
- storage.contract.test.ts: parameterized over both adapters; wired as
  `pnpm contract` and added to CI.
- seed.ts (`pnpm --filter server seed`): creates demo project "The Glass Harbor"
  — 3 chapters of prose, 4 linked characters, 1 world location, 6-node board.
- Dockerfile + compose wiring for the server runtime.

Acceptance: seed project opens with 3 chapters, 4 linked characters, 1 board.

packages/ui/src/fonts.ts

@@ -0,0 +1,36 @@
+/**
+ * Font families per theme. See PLAN.md §4.7.
+ * System fonts only — no network fetches.
+ */
+
+export interface FontSet {
+  /** UI chrome font. */
+  ui: string;
+  /** Body / prose font. */
+  body: string;
+  /** Monospace for code / terminal theme. */
+  mono: string;
+}
+
+export const FONTS: Record<string, FontSet> = {
+  ink: {
+    ui: "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif",
+    body: "Georgia, 'Times New Roman', serif",
+    mono: "'SFMono-Regular', ui-monospace, 'Cascadia Code', Consolas, monospace",
+  },
+  parchment: {
+    ui: "Georgia, 'Times New Roman', serif",
+    body: "Georgia, 'Times New Roman', serif",
+    mono: "'SFMono-Regular', ui-monospace, Consolas, monospace",
+  },
+  nocturne: {
+    ui: "-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif",
+    body: "Georgia, 'Times New Roman', serif",
+    mono: "'SFMono-Regular', ui-monospace, 'Cascadia Code', Consolas, monospace",
+  },
+  terminal: {
+    ui: "'SFMono-Regular', ui-monospace, 'Cascadia Code', Consolas, monospace",
+    body: "'SFMono-Regular', ui-monospace, Consolas, monospace",
+    mono: "'SFMono-Regular', ui-monospace, Consolas, monospace",
+  },
+};