feat(outbound): add {trend_arrow_emoji} template token for white-on-grey emoji arrows

Adds a new template token {trend_arrow_emoji} that renders trend arrows as emoji:
- ⬆️⬆️ for DoubleUp
- ⬆️ for SingleUp
- ↗️ for FortyFiveUp
- ➡️ for Flat
- ↘️ for FortyFiveDown
- ⬇️ for SingleDown
- ⬇️⬇️ for DoubleDown

These render consistently across platforms as white arrows on grey squares,
providing the visual consistency the user needs for Telegram messages.

Users can now use {trend_arrow_emoji} in their message templates instead of
{trend_arrow} to get the emoji style. Example:
  '{status_emoji} {value} {unit} {trend_arrow_emoji} {time}'

Author: Rob

Common/src/main/java/tk/glucodata/OutboundApi.kt

@@ -462,6 +462,7 @@ object OutboundApi {
             }
         }
         val trendArrow: String get() = trendArrow(trendName)
+        val trendArrowEmoji: String get() = trendArrowEmoji(trendName)
         val iob: Float get() = runCatching { Natives.getIOBvalue(timeMillis) }.getOrDefault(Float.NaN)
         val journal: JournalSnapshot get() = loadJournalSnapshot(timeMillis)
         val displayText: String
@@ -541,6 +542,7 @@ object OutboundApi {
             })
             .replace("{trend}", reading.trendName)
             .replace("{trend_arrow}", reading.trendArrow)
+            .replace("{trend_arrow_emoji}", reading.trendArrowEmoji)
             .replace("{rate_mgdl}", formatNumber(reading.rateMgdlPerMinute, 1))
             .replace("{rate_mmol}", formatNumber(reading.rateMmolPerMinute, 3))
             .replace("{timestamp}", reading.timeMillis.toString())
@@ -620,6 +622,18 @@ object OutboundApi {
             "DoubleDown" -> "\u2193\u2193"
             else -> "\u2192"
         }
+
+    private fun trendArrowEmoji(trendName: String): String =
+        when (trendName) {
+            "DoubleUp" -> "\u2b06\ufe0f\u2b06\ufe0f"       // \u2b06\ufe0f\u2b06\ufe0f
+            "SingleUp" -> "\u2b06\ufe0f"                    // \u2b06\ufe0f
+            "FortyFiveUp" -> "\u2197\ufe0f"                 // \u2197\ufe0f
+            "Flat" -> "\u27a1\ufe0f"                        // \u27a1\ufe0f
+            "FortyFiveDown" -> "\u2198\ufe0f"               // \u2198\ufe0f
+            "SingleDown" -> "\u2b07\ufe0f"                  // \u2b07\ufe0f
+            "DoubleDown" -> "\u2b07\ufe0f\u2b07\ufe0f"      // \u2b07\ufe0f\u2b07\ufe0f
+            else -> "\u27a1\ufe0f"                          // \u27a1\ufe0f
+        }
 }
 
 class OutboundApiWorker(

Common/src/main/java/tk/glucodata/OutboundApiSettings.kt

@@ -66,6 +66,9 @@ object OutboundApiSettings {
         "{value} {unit} {trend_arrow} RAW:{raw} ({rate_mgdl} mg/dL/min) IOB:{iob} COB:{cob} {time}"
     const val DEFAULT_CHAT_TEMPLATE =
         "{status_emoji} {value} {unit} {trend_arrow} {time}"
+    // Alternative with emoji trend arrows (renders as white arrows on grey squares)
+    const val DEFAULT_CHAT_TEMPLATE_EMOJI_ARROWS =
+        "{status_emoji} {value} {unit} {trend_arrow_emoji} {time}"
     // Old default before status tokens were added — used to migrate stored templates on load.
     private const val LEGACY_CHAT_TEMPLATE = "{value} {unit} {trend_arrow} {time}"
     const val DEFAULT_GLUCO_WATCH_TEMPLATE =

Common/src/mobile/java/tk/glucodata/ui/OutboundApiSettingsScreen.kt

@@ -1228,6 +1228,7 @@ private val templateTokens = listOf(
     "{value}",
     "{unit}",
     "{trend_arrow}",
+    "{trend_arrow_emoji}",
     "{time}",
     "{mgdl}",
     "{mmol}",