feat(dictionaries): add DICT/Slob formats and Web Search providers (#4048)

Extends the dictionary system beyond StarDict/MDict with two more open
formats and a pluggable Web Search tier so users can fall back to online
sources when their offline bundles miss a word.

Formats:
- DICT (dictd, RFC 2229): .index + .dict.dz bundles. Shared DictZip
  parsing with StarDict via new dictZip.ts helper.
- Slob (Aard 2): self-contained .slob containers, zlib-compressed
  utf-8 entries; non-zlib/non-utf-8 bundles flagged unsupported at
  import.

Web Search:
- Built-in templates for Google, Urban Dictionary, Merriam-Webster
  (seeded into providerOrder, disabled by default).
- Custom URL templates via %WORD% placeholder, URL-encoded at
  substitution; entries persist in settings.webSearches.
- V1 renders an "Open in {{name}}" external link (iframe embedding is
  blocked by every major target site's X-Frame-Options).

UI:
- CustomDictionaries panel: flat outline-primary buttons for Import /
  Add Web Search, end-aligned type badges for a uniform column,
  hover states, compact tips block.
- Dictionary popup: bottom-right Manage icon (tooltip-only) deep-links
  into Settings → Language → Dictionaries; rounded-corner clipping fix
  on the tab strip.

File picker accepts .index and .slob; importer recognizes DICT and
Slob bundles and reads bundle metadata for friendly names.

Tests cover DICT/Slob readers and providers with real freedict-eng-nld
fixtures, web search substitution + provider rendering, and the new
store CRUD for web searches.

Closes #4038

apps/readest-app/src/app/reader/components/annotator/Annotator.tsx

@@ -51,7 +51,8 @@ import ExportMarkdownDialog from './ExportMarkdownDialog';
 const Annotator: React.FC<{ bookKey: string }> = ({ bookKey }) => {
   const _ = useTranslation();
   const { envConfig, appService } = useEnv();
-  const { settings } = useSettingsStore();
+  const { settings, setSettingsDialogBookKey, setSettingsDialogOpen, setActiveSettingsItemId } =
+    useSettingsStore();
   const { isDarkMode } = useThemeStore();
   const { getConfig, saveConfig, getBookData, updateBooknotes } = useBookDataStore();
   const { getProgress, getView, getViewsById, getViewSettings } = useReaderStore();
@@ -970,6 +971,15 @@ const Annotator: React.FC<{ bookKey: string }> = ({ bookKey }) => {
           popupWidth={dictPopupWidth}
           popupHeight={dictPopupHeight}
           onDismiss={handleDismissPopupAndSelection}
+          onManage={() => {
+            // Dismiss the popup so the user returns to the reader cleanly
+            // when they close settings; the dictionaries sub-page in the
+            // SettingsDialog is enough surface for managing providers.
+            handleDismissPopupAndSelection();
+            setSettingsDialogBookKey(bookKey);
+            setActiveSettingsItemId('settings.language.dictionaries.manage');
+            setSettingsDialogOpen(true);
+          }}
         />
       )}
       {showDeepLPopup && trianglePosition && translatorPopupPosition && (

apps/readest-app/src/app/reader/components/annotator/DictionaryPopup.tsx

@@ -1,5 +1,5 @@
 import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
-import { MdArrowBack } from 'react-icons/md';
+import { MdArrowBack, MdSettings } from 'react-icons/md';
 import clsx from 'clsx';
 import { openUrl } from '@tauri-apps/plugin-opener';
 
@@ -22,6 +22,13 @@ interface DictionaryPopupProps {
   popupWidth: number;
   popupHeight: number;
   onDismiss?: () => void;
+  /**
+   * Invoked when the user clicks the bottom-right "Manage Dictionaries"
+   * icon. The host (Annotator) decides how to navigate — typically by
+   * opening the SettingsDialog and deep-linking to the dictionaries
+   * sub-page.
+   */
+  onManage?: () => void;
 }
 
 interface TabState {
@@ -45,6 +52,7 @@ const DictionaryPopup: React.FC<DictionaryPopupProps> = ({
   popupWidth,
   popupHeight,
   onDismiss,
+  onManage,
 }) => {
   const _ = useTranslation();
   const { envConfig, appService } = useEnv();
@@ -294,7 +302,11 @@ const DictionaryPopup: React.FC<DictionaryPopupProps> = ({
       className='select-text'
       onDismiss={onDismiss}
     >
-      <div className='relative flex h-full flex-col'>
+      {/* `overflow-hidden rounded-lg` clips child surfaces (the tab strip's
+          gray bg, the bottom footer divider, etc.) to the popup's rounded
+          shape — without it the tab bar's `bg-base-300/40` and `border-b`
+          paint into the corner area and break the rounded edge. */}
+      <div className='relative flex h-full flex-col overflow-hidden rounded-lg'>
         {providers.length > 1 && (
           <div
             role='tablist'
@@ -386,14 +398,33 @@ const DictionaryPopup: React.FC<DictionaryPopupProps> = ({
           })
         )}
 
-        {sourceLabel && (
-          <footer
-            className='not-eink:opacity-60 mt-auto flex items-center px-4 py-2 text-sm'
-            title={`Source: ${sourceLabel}`}
-          >
-            {/* min-w-0 lets the truncate engage inside the flex parent —
-                without it the span sizes to its content and overflows. */}
-            <span className='min-w-0 flex-1 truncate'>Source: {sourceLabel}</span>
+        {/* Footer always renders so the manage-dictionaries icon has a
+            consistent home at the bottom-right of every tab. The source
+            label fills the left side when present; otherwise the spacer
+            pushes the icon to the right. */}
+        {(sourceLabel || onManage) && (
+          <footer className='mt-auto flex shrink-0 items-center gap-2 px-3 py-1.5'>
+            {sourceLabel ? (
+              <span
+                className='not-eink:opacity-60 min-w-0 flex-1 truncate text-sm'
+                title={`Source: ${sourceLabel}`}
+              >
+                Source: {sourceLabel}
+              </span>
+            ) : (
+              <span className='flex-1' />
+            )}
+            {onManage && (
+              <button
+                type='button'
+                onClick={onManage}
+                aria-label={_('Manage Dictionaries')}
+                title={_('Manage Dictionaries')}
+                className='btn btn-ghost btn-square btn-xs text-base-content/60 hover:text-base-content not-eink:hover:bg-base-200/60 shrink-0'
+              >
+                <MdSettings size={16} />
+              </button>
+            )}
           </footer>
         )}
       </div>