fix: Improve microphone device selection to avoid alias deviceIds

- Add isAlias() helper to identify 'default' and 'communications' aliases
- Prefer actual device IDs (long strings) over alias IDs
- For alias deviceIds, use {audio: true} to let system choose
- For real deviceIds, try exact first, then ideal as fallback
- Add debug logging for isSecureContext and alias detection

This fixes the "Could not start audio source" error when Electron tries
to open a microphone using exact: 'communications' constraint.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/src/pages/meeting-detail.html

@@ -421,6 +421,9 @@
           return;
         }
 
+        // Debug: Check if we're in a secure context
+        console.log('isSecureContext:', window.isSecureContext);
+
         // Check for available audio devices first
         const devices = await navigator.mediaDevices.enumerateDevices();
         const audioInputs = devices.filter(d => d.kind === 'audioinput');
@@ -431,40 +434,56 @@
           return;
         }
 
+        // Helper to identify alias deviceIds (not real device IDs)
+        const isAlias = (id) => id === 'default' || id === 'communications';
+
         // Filter out Stereo Mix (立體聲混音) - it's not a real microphone
         const realMicrophones = audioInputs.filter(d =>
           !d.label.includes('立體聲混音') &&
-          !d.label.toLowerCase().includes('stereo mix') &&
+          !d.label.toLowerCase().includes('stereo mix')
-          d.deviceId !== 'default'  // Skip default which might be Stereo Mix
         );
 
-        // Prefer communications device or actual microphone
+        // Prefer actual device IDs (long strings), not aliases like 'default' or 'communications'
+        // First try to find a real microphone with actual deviceId
         let selectedMic = realMicrophones.find(d =>
-          d.deviceId === 'communications' ||
+          !isAlias(d.deviceId) && (
-          d.label.includes('麥克風') ||
+            d.label.includes('麥克風') ||
-          d.label.toLowerCase().includes('microphone')
+            d.label.toLowerCase().includes('microphone')
-        ) || realMicrophones[0];
+          )
+        ) || realMicrophones.find(d => !isAlias(d.deviceId)) || realMicrophones[0];
 
         console.log('Real microphones found:', realMicrophones.length);
         console.log('Selected microphone:', selectedMic);
+        console.log('Selected deviceId is alias:', selectedMic ? isAlias(selectedMic.deviceId) : 'N/A');
 
         if (!selectedMic) {
           alert('No real microphone found. Only Stereo Mix detected. Please connect a microphone.');
           return;
         }
 
-        // Try with the selected microphone
+        // Get microphone stream with proper constraints handling
         try {
-          mediaStream = await navigator.mediaDevices.getUserMedia({
+          if (isAlias(selectedMic.deviceId)) {
-            audio: { deviceId: { exact: selectedMic.deviceId } }
+            // For alias deviceIds (default/communications), let the system choose
-          });
+            console.log('Using system default (alias detected)');
+            mediaStream = await navigator.mediaDevices.getUserMedia({ audio: true });
+          } else {
+            // For real deviceIds, try exact first, then ideal as fallback
+            try {
+              mediaStream = await navigator.mediaDevices.getUserMedia({
+                audio: { deviceId: { exact: selectedMic.deviceId } }
+              });
+            } catch (exactErr) {
+              console.warn('Exact device ID failed, trying ideal:', exactErr);
+              mediaStream = await navigator.mediaDevices.getUserMedia({
+                audio: { deviceId: { ideal: selectedMic.deviceId } }
+              });
+            }
+          }
           console.log('Successfully connected to:', selectedMic.label);
-        } catch (exactErr) {
+        } catch (err) {
-          console.warn('Exact device ID failed, trying preferred:', exactErr);
+          console.error('getUserMedia failed:', err.name, err.message);
-          // Fallback: try with preferred instead of exact
+          throw err; // Let outer catch handle the error message
-          mediaStream = await navigator.mediaDevices.getUserMedia({
-            audio: { deviceId: selectedMic.deviceId }
-          });
         }
 
         isRecording = true;