fix(ebook-reader): improve image loading, keyboard nav, and progress tracking

- Add enhanced image path lookup (findImageInResources) that tries multiple
  path variations: full path, relative path, filename only, without extension,
  and common extensions (.jpg, .jpeg, .gif, .webp, .svg, .png)
- Fix keyboard navigation by focusing container on reader init
- Implement Kindle-style page display using pageCalculationResult for both
  currentPage and totalPages instead of raw spine index
- Store computed currentPage in state during scroll for UI display
- Extend progress API to send character offset, chapter index, and percentage
  for accurate cross-device sync (backend already supports these fields)

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

@@ -8,6 +8,7 @@ import {
   getCurrentPageFromScroll,
   type PageCalculationResult,
 } from "../ebook/page-calculator";
+import { UniversalReader } from "../reader-shell";
 
 let pageCalculationResult: PageCalculationResult | null = null;
 let isCalculatingPages = false;
@@ -253,14 +254,27 @@ export async function renderSpineItem() {
     state.currentReader.cif.spine[state.currentReader.currentSpineIndex];
   const container = document.getElementById("reader-content");
   if (pageCalculationResult) {
-    const chapter = pageCalculationResult.chapterMap.get(
+    const viewportHeight = window.innerHeight;
+    const currentPage = getCurrentPageFromScroll(
+      pageCalculationResult,
       state.currentReader.currentSpineIndex,
+      container.scrollTop,
+      viewportHeight,
     );
-    if (chapter) {
-      // Reset scroll to start of new chapter
-      container.scrollTop = 0;
-      state.currentReader.currentScrollPosition = 0;
-    }
+
+    // Store computed page for UI display
+    state.currentReader.currentPage = currentPage;
+    setState({ currentReader: state.currentReader });
+
+    const percentage = calculateProgressPercentage(
+      pageCalculationResult,
+      currentPage,
+    );
+    readerEvents.emit("progressUpdated", {
+      currentPage,
+      totalPages: pageCalculationResult.totalPages,
+      percentage,
+    });
   }
   if (!container || !spineItem) return;
   // Get the actual content from resources using the href
@@ -332,8 +346,7 @@ export async function renderSpineItem() {
     if (!src) continue;
 
     // Try different path formats to find the image
-    let blob = resources.get(src);
-    if (!blob) blob = resources.get(src.split("/").pop()); // Try just filename
+    let blob = findImageInResources(resources, src);
 
     if (blob) {
       // Create blob URL - need to do this properly
@@ -355,8 +368,7 @@ function rewriteImageUrls(
   const imgRegex = /<img\s+[^>]*src="([^"]+)"[^>]*>/gi;
   return htmlContent.replace(imgRegex, (match, src) => {
     // Try to find the image in resources
-    const imageBlob =
-      resources.get(src) || resources.get(src.replace(/^.*\//, "")); // Try filename only
+    const imageBlob = findImageInResources(resources, src);
 
     if (imageBlob) {
       const blobUrl = URL.createObjectURL(imageBlob);
@@ -366,6 +378,33 @@ function rewriteImageUrls(
   });
 }
 
+export function findImageInResources(
+  resources: Map<string, Blob>,
+  src: string,
+): Blob | undefined {
+  // Try full path as stored
+  if (resources.has(src)) return resources.get(src);
+  // Try relative path (everything after first /)
+  const firstSlash = src.indexOf("/");
+  if (firstSlash > 0) {
+    const relativePath = src.substring(firstSlash + 1);
+    if (resources.has(relativePath)) return resources.get(relativePath);
+  }
+  // Try filename only
+  const filename = src.split("/").pop();
+  if (filename && resources.has(filename)) return resources.get(filename);
+  // Try without extension
+  const withoutExt = filename?.replace(/\.[^.]+$/, "");
+  if (withoutExt && resources.has(withoutExt)) return resources.get(withoutExt);
+  // Try with common extensions
+  const extensions = [".jpg", ".jpeg", ".gif", ".webp", ".svg", ".png"];
+  for (const ext of extensions) {
+    const withExt = withoutExt + ext;
+    if (resources.has(withExt)) return resources.get(withExt);
+  }
+  return undefined;
+}
+
 async function renderPDFPage() {
   const state = getState();
   if (state.currentReader?.type !== "pdf") return;
@@ -498,10 +537,29 @@ function sendProgressUpdate() {
     currentPage = state.currentReader.currentPage;
   }
 
-  updateReadingProgress(state.readerMetadata.media_item_id, {
-    current_page: currentPage,
-    total_pages: totalPages,
-  });
+  const reader = state.currentReader as UniversalReader;
+  const percentage = totalPages > 0 ? (currentPage / totalPages) * 100 : 0;
+
+  updateReadingProgress(
+    state.readerMetadata.media_item_id,
+    {
+      current_page: currentPage,
+      total_pages: totalPages,
+    },
+    {
+      // Extended data for cross-device sync
+      character: getCharacterOffset(),
+      chapter: reader.currentSpineIndex,
+      percentage: percentage,
+    },
+  );
 
   readerEvents.emit("progressUpdated", { currentPage, totalPages });
 }
+
+function getCharacterOffset(): number {
+  const container = document.getElementById("reader-content");
+  if (!container) return 0;
+  const textContent = container.textContent || "";
+  return textContent.length;
+}

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

@@ -5,17 +5,43 @@ interface ReadingProgress {
   total_pages: number;
 }
 
+interface ExtendedProgress {
+  character?: number;
+  chapter?: number;
+  percentage?: number;
+}
+
 export async function updateReadingProgress(
   mediaItemId: string,
   progress: ReadingProgress,
+  extended?: ExtendedProgress,
 ): Promise<void> {
   if (!mediaItemId || mediaItemId === "undefined") {
     console.warn("Skipping progress update - no valid mediaItemId");
     return;
   }
+  const payload: any = {
+    location: {
+      page: progress.current_page,
+      total_pages: progress.total_pages,
+    },
+  };
+
+  if (extended) {
+    if (extended.character !== undefined) {
+      payload.location.character = extended.character;
+    }
+    if (extended.chapter !== undefined) {
+      payload.location.chapter = extended.chapter;
+    }
+    if (extended.percentage !== undefined) {
+      payload.location.percentage = extended.percentage;
+    }
+  }
+
   const response = await apiPut(
     `/media-items/${mediaItemId}/progress`,
-    progress,
+    payload,
   );
   if (!response.ok) {
     const errorText = await response.text();

web/src/reader/ebook/page-calculator.ts

@@ -1,3 +1,5 @@
+import { findImageInResources } from "../core/reader-navigation";
+
 export interface ChapterPageInfo {
   spineIndex: number;
   spineItemId: string;
@@ -94,7 +96,7 @@ async function renderContentForMeasurement(
     const src = img.getAttribute("src");
     if (!src) continue;
 
-    let blob = resources.get(src);
+    let blob = findImageInResources(resources, src);
     if (!blob) blob = resources.get(src.split("/").pop() || "");
 
     if (blob) {

web/src/reader/reader-shell.ts

@@ -7,7 +7,7 @@ import { createNavigationAPI } from "./core/reader-navigation";
 import { readerEvents } from "./core/reader-events";
 import { renderSpineItem } from "./core/reader-navigation";
 
-interface UniversalReader {
+export interface UniversalReader {
   type: "ebook";
   cif: any;
   currentSpineIndex: number;
@@ -145,6 +145,9 @@ async function initializeReader(): Promise<void> {
     readerEvents.emit("readerReady", currentReader);
     // Render the initial chapter content
     await renderSpineItem();
+    // Focus the content container so keyboard navigation works immediately
+    const container = document.getElementById("reader-content");
+    container?.focus();
     // Initialize page calculation for dynamic page numbers
     setTimeout(async () => {
       const { initializePageCalculation } =
@@ -240,6 +243,10 @@ Alpine.data("readerShell", () => ({
     if (!state.currentReader) return 0;
 
     if (state.currentReader.type === "ebook") {
+      // Use stored computed page if available
+      if (state.currentReader.currentPage) {
+        return state.currentReader.currentPage;
+      }
       return state.currentReader.currentSpineIndex + 1;
     }
     return state.currentReader.currentPage;
@@ -250,6 +257,10 @@ Alpine.data("readerShell", () => ({
     if (!state.currentReader || !state.readerMetadata) return 0;
 
     if (state.currentReader.type === "ebook") {
+      // Use dynamic page calculation if available
+      if (state.currentReader.pageCalculationResult) {
+        return state.currentReader.pageCalculationResult.totalPages;
+      }
       return state.currentReader.cif.spine.length;
     } else if (state.currentReader.type === "pdf") {
       return state.readerMetadata.total_pages || 0;