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.

apps/web/src/App.tsx

@@ -0,0 +1,63 @@
+import { useState, useEffect } from "react";
+import { Routes, Route } from "react-router-dom";
+import { Sidebar, Topbar, CommandPalette } from "./components/index.js";
+import { ToastViewport } from "@pubscript/ui";
+import { Write } from "./routes/Write.js";
+import { Characters } from "./routes/Characters.js";
+import { Plot } from "./routes/Plot.js";
+import { Whiteboard } from "./routes/Whiteboard.js";
+import { AI } from "./routes/AI.js";
+import { Projects } from "./routes/Projects.js";
+import { Settings } from "./routes/Settings.js";
+import { Admin } from "./routes/Admin.js";
+
+const NAV = [
+  { to: "/", label: "Write", icon: "✎", end: true },
+  { to: "/characters", label: "Characters", icon: "👤", end: false },
+  { to: "/plot", label: "Plot", icon: "🗺", end: false },
+  { to: "/whiteboard", label: "Whiteboard", icon: "🧩", end: false },
+  { to: "/ai", label: "AI", icon: "✨", end: false },
+  { to: "/projects", label: "Projects", icon: "📁", end: false },
+  { to: "/settings", label: "Settings", icon: "⚙", end: false },
+  { to: "/admin", label: "Admin", icon: "🛠", end: false },
+];
+
+export default function App() {
+  const [paletteOpen, setPaletteOpen] = useState(false);
+
+  useEffect(() => {
+    const onKey = (e: KeyboardEvent) => {
+      if ((e.metaKey || e.ctrlKey) && e.key.toLowerCase() === "k") {
+        e.preventDefault();
+        setPaletteOpen((o) => !o);
+      }
+    };
+    document.addEventListener("keydown", onKey);
+    return () => document.removeEventListener("keydown", onKey);
+  }, []);
+
+  return (
+    <div className="ps-app">
+      <Sidebar nav={NAV} />
+      <div style={{ display: "flex", flexDirection: "column", height: "100%" }}>
+        <Topbar onOpenPalette={() => setPaletteOpen(true)} />
+        <main className="ps-main" style={{ flex: 1, overflow: "hidden" }}>
+          <Routes>
+            <Route path="/" element={<Write />} />
+            <Route path="/characters" element={<Characters />} />
+            <Route path="/plot" element={<Plot />} />
+            <Route path="/whiteboard" element={<Whiteboard />} />
+            <Route path="/ai" element={<AI />} />
+            <Route path="/projects" element={<Projects />} />
+            <Route path="/settings" element={<Settings />} />
+            <Route path="/admin" element={<Admin />} />
+            <Route path="*" element={<Write />} />
+          </Routes>
+        </main>
+      </div>
+
+      <CommandPalette open={paletteOpen} onClose={() => setPaletteOpen(false)} nav={NAV} />
+      <ToastViewport />
+    </div>
+  );
+}