feat(reader): add core infrastructure for feature-based architecture

- Add reader-context.ts: defines ReaderContext interface and factory
- Add reader-events.ts: event bus for feature communication
- Add reader-state.ts: centralized state management
- Add reader-navigation.ts: unified navigation and rendering API
- Add reader-services.ts: shared services (progress, chapters)
- Establishes foundation for Feature Registration Pattern

web/src/reader/core/reader-context.ts

@@ -0,0 +1,84 @@
+import type { ReaderMetadata } from "../../types/reader";
+
+type ReaderType = "ebook" | "pdf" | "comic" | "manga";
+
+interface UniversalReader {
+  type: "ebook";
+  cif: any;
+  currentSpineIndex: number;
+}
+
+interface PDFReader {
+  type: "pdf";
+  doc: any;
+  currentPage: number;
+}
+
+interface ComicReader {
+  type: "comic";
+  images: Blob[];
+  currentPage: number;
+}
+
+interface MangaReader {
+  type: "manga";
+  images: Blob[];
+  currentPage: number;
+  readingDirection: "rtl" | "vertical";
+}
+
+type CurrentReader = UniversalReader | PDFReader | ComicReader | MangaReader;
+
+export interface ReaderContext {
+  getState: () => {
+    currentReader: CurrentReader | null;
+    readerMetadata: ReaderMetadata | null;
+  };
+  setState: (updates: Partial<ReaderState>) => void;
+  navigation: {
+    nextPage: () => void;
+    previousPage: () => void;
+    goToPage: (page: number) => void;
+    goToChapter: (chapterIndex: number) => void;
+  };
+  render: () => void;
+  elements: {
+    readerContent: HTMLElement;
+    chrome: HTMLElement | null;
+    progressDisplay: HTMLElement | null;
+  };
+  events: {
+    on: (event: string, handler: Function) => void;
+    emit: (event: string, data?: any) => void;
+  };
+}
+
+export interface ReaderState {
+  currentReader: CurrentReader | null;
+  readerMetadata: ReaderMetadata | null;
+}
+
+export function createReaderContext(
+  getState: () => ReaderState,
+  setState: (updates: Partial<ReaderState>) => void,
+  navigation: ReaderContext["navigation"],
+  render: () => void,
+): ReaderContext {
+  return {
+    getState,
+    setState,
+    navigation,
+    render,
+    elements: {
+      readerContent: document.getElementById("reader-content")!,
+      chrome: document.getElementById("reader-chrome"),
+      progressDisplay: document.getElementById("progress-display"),
+    },
+    events: {
+      on: (event: string, handler: Function) => readerEvents.on(event, handler),
+      emit: (event: string, data?: any) => readerEvents.emit(event, data),
+    },
+  };
+}
+
+import { readerEvents } from "./reader-events";