fix(android): collapse relativeTime returns to one branch (detekt ReturnCount)

Folded the early-return ladder in `relativeTime` into a single `when`
returning the result. Same four cutoff windows — `<1h` / `<24h` /
`<7d` / older — just bound to a single expression so detekt's
ReturnCount (limit 2) is satisfied. The opening "unparseable → return
raw" still uses an early return; that's only 2 total now.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/history/ui/HistoryTab.kt

@@ -185,22 +185,24 @@ private const val DAYS_PER_WEEK = 7L
  * up the row over malformed timestamps.
  */
 private fun relativeTime(iso: String): String {
-    val t = runCatching { OffsetDateTime.parse(iso) }.getOrNull() ?: return iso
-    val local = t.atZoneSameInstant(ZoneId.systemDefault())
+    val parsed = runCatching { OffsetDateTime.parse(iso) }.getOrNull()
+        ?: return iso
+    val local = parsed.atZoneSameInstant(ZoneId.systemDefault())
     val now = OffsetDateTime.now(ZoneId.systemDefault())
     val minutes = ChronoUnit.MINUTES.between(local, now)
-    if (minutes < MINUTES_PER_HOUR) {
-        val m = if (minutes < 1) 1 else minutes
-        return "${m}m ago"
-    }
     val hours = ChronoUnit.HOURS.between(local, now)
-    if (hours < HOURS_PER_DAY) return "${hours}h ago"
     val days = ChronoUnit.DAYS.between(local, now)
-    if (days < DAYS_PER_WEEK) {
-        val dow = local.dayOfWeek.getDisplayName(TextStyle.SHORT, Locale.getDefault())
-        val time = local.toLocalTime().format(DateTimeFormatter.ofPattern("HH:mm"))
-        return "$dow $time"
+    return when {
+        minutes < MINUTES_PER_HOUR -> "${minutes.coerceAtLeast(1)}m ago"
+        hours < HOURS_PER_DAY -> "${hours}h ago"
+        days < DAYS_PER_WEEK -> {
+            val dow = local.dayOfWeek.getDisplayName(TextStyle.SHORT, Locale.getDefault())
+            val time = local.toLocalTime().format(DateTimeFormatter.ofPattern("HH:mm"))
+            "$dow $time"
+        }
+        else -> {
+            val pattern = if (local.year == now.year) "MMM d" else "MMM d, yyyy"
+            local.toLocalDate().format(DateTimeFormatter.ofPattern(pattern))
+        }
     }
-    val pattern = if (local.year == now.year) "MMM d" else "MMM d, yyyy"
-    return local.toLocalDate().format(DateTimeFormatter.ofPattern(pattern))
 }