Use the standard glyphs for share, look up and ask

Share was already the Material share icon in both top bars, but appeared as
bare text in the couplet actions and under an assistant's answer, so the same
action looked like two different things. It now carries the glyph everywhere.

The selection-menu entries had no icons of their own, so the system drew the
app logo three times over. Each alias now has the icon for its verb, from
Material's own path data: the share glyph people know from every other app,
a magnifier for the dictionary, and send for handing a question elsewhere.
Whether the floating toolbar draws them is the system's decision, not ours.

"Ask an assistant" had a magnifier, which belongs to searching. It sends.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src/main/AndroidManifest.xml

@@ -44,6 +44,7 @@
 
         <activity-alias
             android:name=".LookUpText"
+            android:icon="@drawable/ic_lookup"
             android:targetActivity=".ProcessTextActivity"
             android:exported="true"
             android:label="@string/look_up">
@@ -56,6 +57,7 @@
 
         <activity-alias
             android:name=".AskAssistantText"
+            android:icon="@drawable/ic_ask"
             android:targetActivity=".ProcessTextActivity"
             android:exported="true"
             android:label="@string/assistant_ask">
@@ -68,6 +70,7 @@
 
         <activity-alias
             android:name=".ShareText"
+            android:icon="@drawable/ic_share"
             android:targetActivity=".ProcessTextActivity"
             android:exported="true"
             android:label="@string/share">