feat: add recent session switchers

apps/android/app/src/test/java/com/steipete/clawdis/node/ui/chat/SessionFiltersTest.kt

@@ -0,0 +1,35 @@
+package com.steipete.clawdis.node.ui.chat
+
+import com.steipete.clawdis.node.chat.ChatSessionEntry
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class SessionFiltersTest {
+  @Test
+  fun sessionChoicesPreferMainAndRecent() {
+    val now = 1_700_000_000_000L
+    val recent1 = now - 2 * 60 * 60 * 1000L
+    val recent2 = now - 5 * 60 * 60 * 1000L
+    val stale = now - 26 * 60 * 60 * 1000L
+    val sessions =
+      listOf(
+        ChatSessionEntry(key = "recent-1", updatedAtMs = recent1),
+        ChatSessionEntry(key = "main", updatedAtMs = stale),
+        ChatSessionEntry(key = "old-1", updatedAtMs = stale),
+        ChatSessionEntry(key = "recent-2", updatedAtMs = recent2),
+      )
+
+    val result = resolveSessionChoices("main", sessions, nowMs = now).map { it.key }
+    assertEquals(listOf("main", "recent-1", "recent-2"), result)
+  }
+
+  @Test
+  fun sessionChoicesIncludeCurrentWhenMissing() {
+    val now = 1_700_000_000_000L
+    val recent = now - 10 * 60 * 1000L
+    val sessions = listOf(ChatSessionEntry(key = "main", updatedAtMs = recent))
+
+    val result = resolveSessionChoices("custom", sessions, nowMs = now).map { it.key }
+    assertEquals(listOf("main", "custom"), result)
+  }
+}