refactor(sessions): extract search formatting and paging logic

Extract SessionSearchFormatting and SessionsPaging helpers.
Deduplicate paging calculation in SessionsViewModel and add unit tests.

app/src/test/java/com/m57/hermescontrol/ui/sessions/SessionSearchFormattingTest.kt

@@ -0,0 +1,72 @@
+package com.m57.hermescontrol.ui.sessions
+
+import com.m57.hermescontrol.data.model.SessionSearchResult
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class SessionSearchFormattingTest {
+    @Test
+    fun `clean search snippet strips highlight markers from plain text`() {
+        assertEquals(
+            "Find the deployment logs",
+            cleanSearchSnippet(">>>Find<<< the deployment logs"),
+        )
+    }
+
+    @Test
+    fun `clean search snippet extracts text from JSON payload`() {
+        assertEquals(
+            "Find the deployment logs",
+            cleanSearchSnippet("{\"role\":\"user\",\"content\":\">>>Find<<< the deployment logs\"}"),
+        )
+    }
+
+    @Test
+    fun `clean search snippet extracts nested text array`() {
+        assertEquals(
+            "First part second part",
+            cleanSearchSnippet("{\"parts\":[\">>>First<<< part\",\"second part\"]}"),
+        )
+    }
+
+    @Test
+    fun `clean search snippet normalizes whitespace`() {
+        assertEquals(
+            "hello world",
+            cleanSearchSnippet("  hello    world  \n "),
+        )
+    }
+
+    @Test
+    fun `toSessionInfo leaves title null for match layout`() {
+        val searchResult =
+            SessionSearchResult(
+                session_id = "test-123",
+                session_started = 1700000000.0,
+                snippet = "matched query excerpt",
+                source = "cli",
+                model = "test-model",
+            )
+        val info = searchResult.toSessionInfo()
+        assertEquals("test-123", info.id)
+        assertNull(info.title)
+        assertEquals("matched query excerpt", info.preview)
+        assertEquals("cli", info.source)
+        assertEquals("test-model", info.model)
+    }
+
+    @Test
+    fun `formatPlayedAt handles null and negative epoch`() {
+        assertNull(formatPlayedAt(null))
+        assertNull(formatPlayedAt(0.0))
+        assertNull(formatPlayedAt(-100.0))
+    }
+
+    @Test
+    fun `formatPlayedAt returns formatted string for valid timestamp`() {
+        val result = formatPlayedAt(1700000000.0)
+        assertNotNull(result)
+    }
+}

app/src/test/java/com/m57/hermescontrol/ui/sessions/SessionsPagingTest.kt

@@ -0,0 +1,75 @@
+package com.m57.hermescontrol.ui.sessions
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class SessionsPagingTest {
+    @Test
+    fun `resolveInitialPaging hasMore when received full page and total exceeds accumulated`() {
+        val resolution =
+            SessionsPaging.resolveInitialPaging(
+                receivedCount = 50,
+                pageSize = 50,
+                backendTotal = 120,
+                accumulatedCount = 50,
+            )
+        assertTrue(resolution.hasMore)
+        assertEquals(120, resolution.total)
+    }
+
+    @Test
+    fun `resolveInitialPaging no more when received less than page size`() {
+        val resolution =
+            SessionsPaging.resolveInitialPaging(
+                receivedCount = 30,
+                pageSize = 50,
+                backendTotal = 30,
+                accumulatedCount = 30,
+            )
+        assertFalse(resolution.hasMore)
+        assertEquals(30, resolution.total)
+    }
+
+    @Test
+    fun `resolveInitialPaging no more when backendTotal equals accumulated`() {
+        val resolution =
+            SessionsPaging.resolveInitialPaging(
+                receivedCount = 50,
+                pageSize = 50,
+                backendTotal = 50,
+                accumulatedCount = 50,
+            )
+        assertFalse(resolution.hasMore)
+        assertEquals(50, resolution.total)
+    }
+
+    @Test
+    fun `resolveLoadMorePaging hasMore when full page added new items and total exceeds accumulated`() {
+        val resolution =
+            SessionsPaging.resolveLoadMorePaging(
+                receivedCount = 50,
+                pageSize = 50,
+                addedNewItems = true,
+                backendTotal = 150,
+                accumulatedCount = 100,
+            )
+        assertTrue(resolution.hasMore)
+        assertEquals(150, resolution.total)
+    }
+
+    @Test
+    fun `resolveLoadMorePaging no more when no new items added`() {
+        val resolution =
+            SessionsPaging.resolveLoadMorePaging(
+                receivedCount = 50,
+                pageSize = 50,
+                addedNewItems = false,
+                backendTotal = 150,
+                accumulatedCount = 100,
+            )
+        assertFalse(resolution.hasMore)
+        assertEquals(100, resolution.total)
+    }
+}

app/src/test/java/com/m57/hermescontrol/ui/sessions/SessionsViewModelTest.kt

@@ -92,14 +92,6 @@ class SessionsViewModelTest {
         )
     }
 
-    @Test
-    fun `clean search snippet extracts text from JSON payload`() {
-        assertEquals(
-            "Find the deployment logs",
-            cleanSearchSnippet("{\"role\":\"user\",\"content\":\">>>Find<<< the deployment logs\"}"),
-        )
-    }
-
     @Test
     fun `sections request conversations excluding cron and automations from cron`() {
         val vm = createViewModel()