Find in the channel tree and the chat on Android

A find button in the top bar opens a find bar over the tree (clients or
channels) or the conversation on screen, with match stepping, highlights,
only-matches filtering and the desktop's matching options. The tree's
match rule moves to core TreeMatch, which the desktop now uses too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ts3-client/core/src/main/java/com/ts3client/net/TreeMatch.java

@@ -0,0 +1,22 @@
+package com.ts3client.net;
+
+import com.ts3client.text.TextQuery;
+
+/** What finding in the server tree matches a client or a channel on. */
+public final class TreeMatch {
+
+    private TreeMatch() {
+    }
+
+    /** A client by their nickname, or by the name the contacts give them ({@code null} for none). */
+    public static boolean client(TextQuery query, String nickname, String contactName) {
+        return query.matches(nickname) || (contactName != null && query.matches(contactName));
+    }
+
+    /** A channel by its name; a spacer by its caption, unless that only repeats to fill the row. */
+    public static boolean channel(TextQuery query, String name) {
+        Spacers.Spacer spacer = Spacers.parse(name);
+        if (spacer == null) return query.matches(name);
+        return spacer.align() != '*' && query.matches(spacer.caption());
+    }
+}