refactor(chat): extract rpc request tracker with tests

app/src/test/java/com/m57/hermescontrol/ui/chat/ChatRpcRequestTrackerTest.kt

@@ -0,0 +1,94 @@
+package com.m57.hermescontrol.ui.chat
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class ChatRpcRequestTrackerTest {
+    private var currentSessionId: String? = "session-a"
+    private val tracker = ChatRpcRequestTracker { currentSessionId }
+
+    @Test
+    fun trackRequest_andRemoveMethod() {
+        tracker.trackRequest("req-1", "session.create")
+        assertEquals("session.create", tracker.removeMethod("req-1"))
+        assertNull(tracker.removeMethod("req-1"))
+    }
+
+    @Test
+    fun generationIncrement_detectsStaleGenerations() {
+        val gen1 = tracker.nextSessionGeneration()
+        assertEquals(1L, gen1)
+
+        tracker.trackSessionRequest(
+            id = "req-resume-1",
+            method = "session.resume",
+            generation = gen1,
+            sessionId = "session-a",
+        )
+        assertFalse(tracker.isStaleSessionRequest("req-resume-1"))
+
+        val gen2 = tracker.nextSessionGeneration()
+        assertEquals(2L, gen2)
+        assertTrue(tracker.isStaleSessionRequest("req-resume-1"))
+    }
+
+    @Test
+    fun sessionMismatch_marksRequestStale() {
+        val gen = tracker.nextSessionGeneration()
+        tracker.trackSessionRequest(
+            id = "req-2",
+            method = "session.resume",
+            generation = gen,
+            sessionId = "session-a",
+        )
+        assertFalse(tracker.isStaleSessionRequest("req-2"))
+
+        currentSessionId = "session-b"
+        assertTrue(tracker.isStaleSessionRequest("req-2"))
+    }
+
+    @Test
+    fun resumeSequence_marksSupersededResumeStale() {
+        val gen = tracker.nextSessionGeneration()
+        val seq1 = tracker.nextResumeSequence()
+        tracker.trackSessionRequest(
+            id = "req-resume-seq1",
+            method = "session.resume",
+            generation = gen,
+            resumeSequence = seq1,
+            sessionId = "session-a",
+        )
+        assertFalse(tracker.isStaleSessionRequest("req-resume-seq1"))
+
+        val seq2 = tracker.nextResumeSequence()
+        assertEquals(2L, seq2)
+        assertTrue(tracker.isStaleSessionRequest("req-resume-seq1"))
+    }
+
+    @Test
+    fun hydrationSequence_guardsActiveHydration() {
+        val gen = tracker.nextSessionGeneration()
+        val hyd1 = tracker.nextHydrationSequence()
+        assertTrue(tracker.isCurrentHydration("session-a", gen, hyd1))
+
+        val hyd2 = tracker.nextHydrationSequence()
+        assertFalse(tracker.isCurrentHydration("session-a", gen, hyd1))
+        assertTrue(tracker.isCurrentHydration("session-a", gen, hyd2))
+    }
+
+    @Test
+    fun forgetRequest_removesBothTrackingEntries() {
+        tracker.trackSessionRequest(
+            id = "req-forget",
+            method = "session.resume",
+            generation = tracker.sessionGeneration,
+            sessionId = "session-a",
+        )
+        tracker.forgetRequest("req-forget")
+        assertNull(tracker.removeMethod("req-forget"))
+        assertNull(tracker.removeSessionRequest("req-forget"))
+    }
+}