Replace JNA with the FFM API (Panama) for the Opus binding

Bind libopus through java.lang.foreign downcall handles instead of JNA:
the ctl functions are linked with firstVariadicArg(2), and the encoder and
decoder each own a shared Arena holding the handle plus reusable native
PCM/packet buffers, so the hot path only allocates the returned packet.

The library is resolved by system SONAME first, falling back to a bundled
copy extracted from the JAR. Only the Windows x86-64 build is packaged by
default now (-Dnatives.all restores all platforms), since every other
platform ships libopus through its package manager.

Requires Java 26.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

ts3-client/desktop/pom.xml

@@ -12,7 +12,7 @@
 
     <artifactId>ts3-client-desktop</artifactId>
     <name>TS3J Client Desktop Audio</name>
-    <description>Desktop audio backend: Java Sound capture/playback and native Opus via JNA</description>
+    <description>Desktop audio backend: Java Sound capture/playback and native Opus via the FFM API</description>
 
     <dependencies>
         <dependency>
@@ -23,9 +23,43 @@
             <groupId>com.github.manevolent</groupId>
             <artifactId>ts3j</artifactId>
         </dependency>
-        <dependency>
-            <groupId>net.java.dev.jna</groupId>
-            <artifactId>jna</artifactId>
-        </dependency>
     </dependencies>
+
+    <build>
+        <!--
+            Only the Windows x86-64 Opus build is packaged by default: every other
+            supported platform ships libopus through its package manager (or, on
+            macOS, Homebrew), and the FFM binding loads the system library first.
+            Build with -Dnatives.all to bundle the copies for all platforms.
+        -->
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <excludes>
+                    <exclude>darwin/**</exclude>
+                    <exclude>darwin-*/**</exclude>
+                    <exclude>linux-*/**</exclude>
+                    <exclude>win32-x86/**</exclude>
+                </excludes>
+            </resource>
+        </resources>
+    </build>
+
+    <profiles>
+        <profile>
+            <id>all-natives</id>
+            <activation>
+                <property>
+                    <name>natives.all</name>
+                </property>
+            </activation>
+            <build>
+                <resources>
+                    <resource>
+                        <directory>src/main/resources</directory>
+                    </resource>
+                </resources>
+            </build>
+        </profile>
+    </profiles>
 </project>