fix: speak 'Missed readings' when TTS reading is stale

When a glucose reading is older than glucosetimeout (5.5 min), the
periodic TTS now says 'Missed readings' instead of the last known
value. Also replaces the hardcoded '8.7' fallback in testCurrentValue
and the voice settings test button with the same string.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Rob

Common/src/main/java/tk/glucodata/SuperGattCallback.java

@@ -534,7 +534,11 @@ static void dowithglucose(String SerialNumber, int mgdl, float gl, float rate, i
 
         if (!DontTalk) {
             if (dotalk && !alarmSpeechStarted) {
-                talker.selspeak(sglucose.value);
+                long readingAgeMs = System.currentTimeMillis() - timmsec;
+                String toSpeak = readingAgeMs > Notify.glucosetimeout
+                        ? Applic.app.getString(R.string.tts_missed_readings)
+                        : sglucose.value;
+                talker.selspeak(toSpeak);
             }
         }
         if (isWearable) {

Common/src/main/java/tk/glucodata/Talker.java

@@ -310,7 +310,7 @@ public static void testCurrentValue(Context context) {
     if(DontTalk)
         return;
     var current = CurrentDisplaySource.resolveCurrent(Notify.glucosetimeout);
-    var say=(current!=null&&current.getPrimaryStr()!=null)?current.getPrimaryStr():"8.7";
+    var say=(current!=null&&current.getPrimaryStr()!=null)?current.getPrimaryStr():context.getString(R.string.tts_missed_readings);
     var talk=SuperGattCallback.talker;
     if(talk!=null && talk.engineReady) {
         talk.setvalues();
@@ -888,7 +888,7 @@ public  void onNothingSelected (AdapterView<?> parent) {
         });
     test.setOnClickListener(v->  {
         var current = CurrentDisplaySource.resolveCurrent(Notify.glucosetimeout);
-        var say=(current!=null&&current.getPrimaryStr()!=null)?current.getPrimaryStr():"8.7";
+        var say=(current!=null&&current.getPrimaryStr()!=null)?current.getPrimaryStr():context.getString(R.string.tts_missed_readings);
         getvalues.run();
         if(istalking()) {
             var talk=SuperGattCallback.talker;

Common/src/main/res/values/strings.xml

@@ -288,6 +288,7 @@
  <string name="streamhistory">Bluetooth History</string>
  <string name="libreisviewed">Spy views</string>
  <string name="novalue">No value</string>
+ <string name="tts_missed_readings">Missed readings</string>
  <string name="talk">Talk</string>
  <string name="watches">Watch</string>
  <string name="menus">Menus</string>