CHUNK #3: Writing Surface — editor wiring, storage view, polish

Complete the Writing Surface chunk: wire the web writing view to the
offline-first storage adapter, finish the editor package exports, and
apply Step 4 polish (SVG monogram logo, real project in the sidebar,
font settings → CSS variables).

Editor package
- Re-export EditorContent + Editor type from @pubscript/editor so the
  web app never imports TipTap directly.

Web writing view (apps/web)
- project-store (zustand) over storageLocal: project, chapters, active
  chapter, autosave via createAutosave, idle detection via
  createIdleDetector.
- Client-side seed mirroring the server seed ("The Glass Harbor").
- WritingView component: editor + autosave label + word/scene count +
  chapter nav; wire the /write route inside AppShell.
- Import editor.css in main.tsx.

Core storage contract
- Extend StorageAdapter with createBook/listBooks/listChapters;
  implement in local + server adapters; update contract test mock.

Polish
- Sidebar: SVG monogram logo + live project title/word count instead
  of the placeholder "The Silent Cartographer".
- Fonts: applyFontSettings() in the theme engine writes --ps-font-*
  variables; .ps-content reads --ps-font-size/leading/measure; settings
  store applies fontSize on boot and change.

Docs
- PLAN.md: CHUNK #3 → in progress.
- CHUNK#3_PROGRESS.md: steps 1–3 done, step 4 polish in progress.

Verified: full workspace typecheck clean, lint clean, core 24 / ui 5 /
editor 7 tests pass, web build clean. (server vitest hits EADDRINUSE on
8080 — pre-existing Docker WordPress port conflict, unrelated.)

packages/core/src/autosave.test.ts

@@ -16,6 +16,15 @@ function mockAdapter(): StorageAdapter & { saved: DocumentRef[] } {
     async getProject() {
       throw new Error("not implemented");
     },
+    async createBook() {
+      throw new Error("not implemented");
+    },
+    async listBooks() {
+      return [];
+    },
+    async listChapters() {
+      return [];
+    },
     async getChapter() {
       return null;
     },