feat: /testcall /testecho /testmic — local audio diagnostics

- /testcall: plays 3 tones (440/880/660Hz) to test speaker
- /testecho: mic → speaker loopback with 100ms delay (/stopecho to end)
- /testmic: records 3 seconds, plays back (tests both mic + speaker)

No relay or peer needed — pure local browser audio.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-server/src/routes/web.rs

@@ -2068,6 +2068,97 @@ async function doSend() {
     return;
   }
   if (text === '/call') { startCall(); return; }
+  if (text === '/testcall' || text === '/testtone') {
+    addSys('Audio test: playing 440Hz tone for 3 seconds...');
+    try {
+      const ctx = new AudioContext({ sampleRate: 48000 });
+      const osc = ctx.createOscillator();
+      osc.type = 'sine';
+      osc.frequency.value = 440;
+      osc.connect(ctx.destination);
+      osc.start();
+      setTimeout(() => {
+        osc.frequency.value = 880;
+        addSys('Audio test: 880Hz...');
+      }, 1000);
+      setTimeout(() => {
+        osc.frequency.value = 660;
+        addSys('Audio test: 660Hz...');
+      }, 2000);
+      setTimeout(() => {
+        osc.stop();
+        ctx.close();
+        addSys('Audio test: done. If you heard 3 tones, speaker works.');
+      }, 3000);
+    } catch(e) { addSys('Audio test failed: ' + e.message); }
+    return;
+  }
+  if (text === '/testecho') {
+    addSys('Echo test: speak into mic, you should hear yourself...');
+    addSys('Type /stopecho to stop.');
+    try {
+      const ctx = new AudioContext({ sampleRate: 48000 });
+      const stream = await navigator.mediaDevices.getUserMedia({
+        audio: { sampleRate: 48000, channelCount: 1, echoCancellation: false, noiseSuppression: false }
+      });
+      const source = ctx.createMediaStreamSource(stream);
+      // Direct mic → speaker loopback (with small delay to avoid feedback)
+      const delay = ctx.createDelay(0.15);
+      delay.delayTime.value = 0.1;
+      source.connect(delay);
+      delay.connect(ctx.destination);
+      addSys('Echo active \u2014 mic \u2192 speaker (100ms delay)');
+      window._echoTest = { ctx, stream, source, delay };
+    } catch(e) { addSys('Echo test failed: ' + e.message); }
+    return;
+  }
+  if (text === '/stopecho') {
+    if (window._echoTest) {
+      window._echoTest.stream.getTracks().forEach(t => t.stop());
+      window._echoTest.source.disconnect();
+      window._echoTest.delay.disconnect();
+      window._echoTest.ctx.close();
+      window._echoTest = null;
+      addSys('Echo test stopped.');
+    } else { addSys('No echo test running.'); }
+    return;
+  }
+  if (text === '/testmic') {
+    addSys('Mic test: recording 3 seconds, then playback...');
+    try {
+      const ctx = new AudioContext({ sampleRate: 48000 });
+      const stream = await navigator.mediaDevices.getUserMedia({
+        audio: { sampleRate: 48000, channelCount: 1, echoCancellation: true, noiseSuppression: true }
+      });
+      const source = ctx.createMediaStreamSource(stream);
+      const processor = ctx.createScriptProcessor(4096, 1, 1);
+      const recorded = [];
+      processor.onaudioprocess = (e) => {
+        recorded.push(new Float32Array(e.inputBuffer.getChannelData(0)));
+      };
+      source.connect(processor);
+      processor.connect(ctx.destination);
+      addSys('Recording... speak now');
+      setTimeout(() => {
+        processor.disconnect();
+        source.disconnect();
+        stream.getTracks().forEach(t => t.stop());
+        // Concatenate and play back
+        const total = recorded.reduce((s, a) => s + a.length, 0);
+        const buffer = ctx.createBuffer(1, total, 48000);
+        const channel = buffer.getChannelData(0);
+        let offset = 0;
+        for (const chunk of recorded) { channel.set(chunk, offset); offset += chunk.length; }
+        addSys('Playing back ' + (total / 48000).toFixed(1) + 's of audio...');
+        const playSource = ctx.createBufferSource();
+        playSource.buffer = buffer;
+        playSource.connect(ctx.destination);
+        playSource.start();
+        playSource.onended = () => { ctx.close(); addSys('Mic test done. If you heard yourself, mic + speaker work.'); };
+      }, 3000);
+    } catch(e) { addSys('Mic test failed: ' + e.message); }
+    return;
+  }
   if (text === '/hangup' || text === '/end') { hangupCall(); return; }
   if (text === '/accept') { acceptCall(); return; }
   if (text === '/reject') { rejectCall(); return; }