Offline dictionary (#45)

* Added support for external dictionary apps and a dictionary settings sheet.

* Refactored external dictionary integration and improved package visibility

 - Updated `AndroidManifest.xml` with `<queries>` for common dictionary apps and intent actions (`PROCESS_TEXT`, `SEARCH`, `SEND`) to support Android 11+ package visibility.
 - Refactored `ExternalDictionaryHelper` to streamline dictionary discovery using `Intent.ACTION_PROCESS_TEXT` and `colordict.intent.action.SEARCH`.
 - Added a package blocklist in `ExternalDictionaryHelper` to filter out system services (e.g., Samsung Pass, GMS) from dictionary lists.
  - Simplified `launchDictionary` logic to prioritize `PROCESS_TEXT` intents.
 - Fixed a bug in `PdfViewerScreen` to only show the dictionary upsell dialog when `useOnlineDictionary` is enabled.

* Refactored dictionary settings into a dialog and updated dictionary selection logic.

- Renamed `DictionarySettingsSheet` to `DictionarySettingsDialog` and converted it from a bottom sheet to a formal dialog.
- Redesigned the dictionary settings UI with a clearer distinction between AI and external app modes.
- Added a "Search" option to the external dictionary list that triggers a web search.
- Updated `ExternalDictionaryHelper` to include a package blocklist and support for generic web search intents.
- Simplified `PdfHelper` by removing Pro user checks for the "Dictionary" action.
- Updated icons for dictionary settings across the EPUB and PDF readers.

app/src/main/AndroidManifest.xml

@@ -11,6 +11,26 @@
         </intent>
     </queries>
 
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.PROCESS_TEXT" />
+            <data android:mimeType="text/plain" />
+        </intent>
+        <intent>
+            <action android:name="colordict.intent.action.SEARCH" />
+        </intent>
+        <intent>
+            <action android:name="android.intent.action.SEND" />
+            <data android:mimeType="text/plain" />
+        </intent>
+
+        <package android:name="it.t_arn.aard2" />
+        <package android:name="io.github.mvasilev.dictionary" />
+        <package android:name="com.github.tngande.ossdict" />
+        <package android:name="com.gaurav.lookup" />
+        <package android:name="com.randallbaltazar.lookup" />
+    </queries>
+
     <application
         android:name=".MyApplication"
         android:allowBackup="true"