feat(entity): Chunk #4 data layer + entity UI (characters & world-building)

Data layer:
- Fuzzy scorer (packages/core/src/fuzzy.ts) with index recovery + unit tests
- Backlink computation (packages/core/src/backlinks.ts) incl. entity-level backlinks
- Consistency checker (packages/core/src/consistency.ts) incl. reciprocity/scope + unit tests
- StorageAdapter contract extended with listEntities/searchEntities/saveEntity/deleteEntity;
  implemented in Local (Dexie) and Server adapters; contract tests cover entity CRUD + ?q= search
- WorldItem.fields now supports list values (keyPeople, rivals); expanded RelationshipKind
- @mention autocomplete extension + picker in the editor package

Entity UI (apps/web/src/features/entities/):
- Generic field renderer (EntityFields) driven by ENTITY_FIELDS/FieldDef
- Tabbed directory with fuzzy search + entity cards (EntitiesView)
- Create/edit/delete drawer (EntityEditor) reusing shared fields
- Relationship editor + force-directed SVG relationship map
- Entity engine stylesheet; wired into nav

Store: project-store entity methods (load/create/update/delete) over the StorageAdapter contract.

CI-green: typecheck, lint, 65 tests, and web build all pass.

apps/web/src/store/settings.ts

@@ -3,24 +3,49 @@ import { applyFontSettings, applyTheme, type ThemeId } from "@pubscript/ui";
 
 export type Density = "compact" | "comfortable";
 
+/** Body typeface for the writing column. All are system stacks (no web fonts). */
+export type FontFamily = "serif" | "sans" | "mono";
+
+export const FONT_FAMILIES: { value: FontFamily; label: string; css: string }[] = [
+  { value: "serif", label: "Georgia Serif", css: 'Georgia, "Times New Roman", serif' },
+  { value: "sans", label: "System Sans", css: '-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif' },
+  { value: "mono", label: "Mono", css: '"SFMono-Regular", ui-monospace, "Cascadia Code", Consolas, monospace' },
+];
+
+/** Resolve a stored font-family enum to its CSS font-family string. */
+export function fontFamilyCss(value: FontFamily): string {
+  const found = FONT_FAMILIES.find((f) => f.value === value);
+  return found?.css ?? FONT_FAMILIES.at(0)?.css ?? "";
+}
+
 export interface AppSettings {
   theme: ThemeId;
   accentColor: string;
   density: Density;
+  fontFamily: FontFamily;
   fontSize: number;
+  leading: number;
+  measure: number;
   showLineNumbers: boolean;
   wordCountGoal: number;
   autoSave: boolean;
+  focusMode: boolean;
+  typewriterMode: boolean;
 }
 
 export const DEFAULT_SETTINGS: AppSettings = {
   theme: "ink",
   accentColor: "#7c8bf5",
   density: "comfortable",
+  fontFamily: "serif",
   fontSize: 15,
+  leading: 1.7,
+  measure: 720,
   showLineNumbers: true,
   wordCountGoal: 80_000,
   autoSave: true,
+  focusMode: false,
+  typewriterMode: false,
 };
 
 const STORAGE_KEY = "pubscript.settings.v1";
@@ -46,14 +71,31 @@ export const useSettings = create<SettingsStore>((set, get) => {
   const initial = loadSettings();
   // Apply the persisted theme + font on boot.
   applyTheme(initial.theme);
-  applyFontSettings({ size: initial.fontSize });
+  applyFontSettings({
+    size: initial.fontSize,
+    leading: initial.leading,
+    measure: initial.measure,
+    family: fontFamilyCss(initial.fontFamily),
+  });
 
   return {
     ...initial,
     set: (patch) => {
       const next = { ...get(), ...patch };
       localStorage.setItem(STORAGE_KEY, JSON.stringify(next));
-      if (patch.fontSize != null) applyFontSettings({ size: next.fontSize });
+      if (
+        patch.fontSize != null ||
+        patch.leading != null ||
+        patch.measure != null ||
+        patch.fontFamily != null
+      ) {
+        applyFontSettings({
+          size: next.fontSize,
+          leading: next.leading,
+          measure: next.measure,
+          family: fontFamilyCss(next.fontFamily),
+        });
+      }
       set(next);
     },
     setTheme: (theme) => {
@@ -63,7 +105,12 @@ export const useSettings = create<SettingsStore>((set, get) => {
     reset: () => {
       localStorage.removeItem(STORAGE_KEY);
       applyTheme(DEFAULT_SETTINGS.theme);
-      applyFontSettings({ size: DEFAULT_SETTINGS.fontSize });
+      applyFontSettings({
+        size: DEFAULT_SETTINGS.fontSize,
+        leading: DEFAULT_SETTINGS.leading,
+        measure: DEFAULT_SETTINGS.measure,
+        family: fontFamilyCss(DEFAULT_SETTINGS.fontFamily),
+      });
       set({ ...DEFAULT_SETTINGS });
     },
   };