feat: pdf reader

frontend/src/components/reader/ReadingSettingsPanel.tsx

@@ -14,7 +14,10 @@ import type {
 import type { SettingsPersistMode } from "../../hooks/useReadingSettings";
 
 interface ReadingSettingsPanelProps {
+  format?: "epub" | "pdf";
   settings: ReadingSettings;
+  pdfScale?: number;
+  onPdfScaleChange?: (scale: number) => void;
   isOpen: boolean;
   onClose: () => void;
   onUpdate: (
@@ -44,7 +47,10 @@ const ORIENTATION_OPTIONS: { value: OrientationLock; labelKey: string }[] = [
 ];
 
 export default function ReadingSettingsPanel({
+  format = "epub",
   settings,
+  pdfScale = 1.25,
+  onPdfScaleChange,
   isOpen,
   onClose,
   onUpdate,
@@ -115,6 +121,26 @@ export default function ReadingSettingsPanel({
             </div>
           </section>
 
+          {format === "pdf" && onPdfScaleChange && (
+            <section className="settings-section">
+              <h3 className="settings-section-title">
+                {t("reader.pdfZoom", { value: Math.round(pdfScale * 100) })}
+              </h3>
+              <input
+                type="range"
+                min="0.75"
+                max="2.5"
+                step="0.05"
+                value={pdfScale}
+                onChange={(e) => onPdfScaleChange(Number(e.target.value))}
+                className="settings-slider"
+                aria-label={t("reader.pdfZoomAria")}
+              />
+            </section>
+          )}
+
+          {format === "epub" && (
+          <>
           <section className="settings-section">
             <h3 className="settings-section-title">{t("reader.font")}</h3>
             <div className="font-grid">
@@ -184,6 +210,8 @@ export default function ReadingSettingsPanel({
               aria-label={t("reader.marginWidthAria")}
             />
           </section>
+          </>
+          )}
 
           <section className="settings-section">
             <h3 className="settings-section-title">