Auto-search detection + live reasoning preview

Auto-search:
- detectSearchQuery() pattern-matches common search prompts in DE+EN
  (weather, news, prices, scores, current events, etc.)
- send() enables webSearch automatically when detected, no manual
  pill needed. Manual pill still works as explicit override.
- 30+ patterns ported from backend lib/chat/detection.ts

Live reasoning preview:
- ReasoningBlock shows first meaningful line as preview label when
  collapsed (max 80 chars, ellipsis). Updates live during streaming.
- "Gedankengang" header + preview line stacked vertically.
- Preview hidden when block is expanded (full text visible).

Tests: 4 new tests for detectSearchQuery (DE patterns, EN patterns,
normal prompts not triggered, short input ignored).

app/src/main/java/dev/kaizen/app/chat/ChatModels.kt

@@ -65,6 +65,24 @@ val chatModes = listOf(
     ChatMode(R.string.mode_audio, KaizenIcons.Music),
 )
 
+private val SEARCH_PATTERNS = listOf(
+    "such nach", "suche nach", "was ist aktuell", "aktuelle", "neueste",
+    "wie ist das wetter", "wetter in", "was passiert gerade", "was ist heute",
+    "aktuelle news", "nachrichten", "was kostet", "aktienkurs", "kurs von",
+    "wer hat gewonnen", "ergebnis von", "stand von", "tabelle von",
+    "öffnungszeiten", "wie spät", "uhrzeit in", "einwohner von",
+    "search for", "look up", "find me", "what is happening",
+    "latest news", "current events", "weather in", "weather today",
+    "stock price", "who won", "what happened", "how much is",
+    "when did", "when was", "who is the current", "what are the latest",
+    "score of", "results of", "opening hours", "population of",
+).map { Regex(it, RegexOption.IGNORE_CASE) }
+
+fun detectSearchQuery(text: String): Boolean {
+    if (text.length < 8) return false
+    return SEARCH_PATTERNS.any { it.containsMatchIn(text) }
+}
+
 @Composable
 fun greeting(hour: Int): String = when (hour) {
     in 5..11 -> stringResource(R.string.greeting_morning)

app/src/main/java/dev/kaizen/app/chat/ChatScreenViewModel.kt

@@ -255,13 +255,17 @@ class ChatScreenViewModel(
                     async { KaizenApi.createConversation(cfg.baseUrl, cfg.token) }
                 } else null
 
+                val searchManual = activeMode == R.string.mode_search
+                val searchAuto = !searchManual && detectSearchQuery(trimmed)
+                val useSearch = searchManual || searchAuto
+
                 KaizenApi.chat(
                     cfg.baseUrl, cfg.token, cfg.model, history,
                     reasoningEffort = reasoningPreset.effort,
                     preferThroughput = reasoningPreset.throughput,
                     attachments = uploadedAtts.takeIf { it.isNotEmpty() },
-                    webSearch = activeMode == R.string.mode_search,
-                    webSearchProvider = if (activeMode == R.string.mode_search && cfg.model.startsWith("vertex:")) webSearchProvider else null,
+                    webSearch = useSearch,
+                    webSearchProvider = if (useSearch && cfg.model.startsWith("vertex:")) webSearchProvider else null,
                     temperature = samplingPrefs.temperature.takeIf { it.enabled }?.value,
                     topP = samplingPrefs.topP.takeIf { it.enabled }?.value,
                     topK = samplingPrefs.topK.takeIf { it.enabled }?.value?.toInt(),

app/src/main/java/dev/kaizen/app/chat/StreamBlocks.kt

@@ -54,6 +54,14 @@ fun ReasoningBlock(reasoning: String, streaming: Boolean = false) {
     val accent = LocalKaizenAccent.current
     var expanded by remember { mutableStateOf(streaming) }
 
+    val previewLine = remember(reasoning) {
+        reasoning.lineSequence()
+            .map { it.trim() }
+            .firstOrNull { it.length > 3 }
+            ?.take(80)
+            ?.let { if (it.length == 80) "$it…" else it }
+    }
+
     val bg = accent.primary.copy(alpha = if (isDark) 0.06f else 0.04f)
     val borderBrush = remember(isDark, accent) {
         Brush.verticalGradient(
@@ -80,13 +88,24 @@ fun ReasoningBlock(reasoning: String, streaming: Boolean = false) {
         ) {
             Icon(KaizenIcons.Brain, null, tint = accent.primary.copy(alpha = 0.75f), modifier = Modifier.size(17.dp))
             Spacer(Modifier.width(9.dp))
-            Text(
-                stringResource(R.string.stream_reasoning),
-                color = cs.onSurfaceVariant.copy(alpha = 0.75f),
-                fontSize = 13.sp,
-                fontWeight = FontWeight.Medium,
-                modifier = Modifier.weight(1f),
-            )
+            Column(Modifier.weight(1f)) {
+                Text(
+                    stringResource(R.string.stream_reasoning),
+                    color = cs.onSurfaceVariant.copy(alpha = 0.75f),
+                    fontSize = 13.sp,
+                    fontWeight = FontWeight.Medium,
+                )
+                if (!expanded && previewLine != null) {
+                    Text(
+                        previewLine,
+                        color = cs.onSurfaceVariant.copy(alpha = 0.40f),
+                        fontSize = 11.sp,
+                        fontWeight = FontWeight.W300,
+                        maxLines = 1,
+                        overflow = TextOverflow.Ellipsis,
+                    )
+                }
+            }
             Icon(
                 if (expanded) KaizenIcons.ChevronUp else KaizenIcons.ChevronDown,
                 null, tint = cs.onSurfaceVariant.copy(alpha = 0.40f), modifier = Modifier.size(15.dp),

app/src/test/java/dev/kaizen/app/DetectSearchTest.kt

@@ -0,0 +1,45 @@
+package dev.kaizen.app
+
+import dev.kaizen.app.chat.detectSearchQuery
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class DetectSearchTest {
+
+    @Test
+    fun detectsGermanSearchPatterns() {
+        assertTrue(detectSearchQuery("Was ist aktuell in der Politik los?"))
+        assertTrue(detectSearchQuery("Suche nach den neuesten Nachrichten"))
+        assertTrue(detectSearchQuery("Wie ist das Wetter in Berlin?"))
+        assertTrue(detectSearchQuery("Was kostet ein Tesla Model 3?"))
+        assertTrue(detectSearchQuery("Aktuelle News zu Apple"))
+        assertTrue(detectSearchQuery("Aktienkurs von Nvidia"))
+    }
+
+    @Test
+    fun detectsEnglishSearchPatterns() {
+        assertTrue(detectSearchQuery("Search for the latest news about AI"))
+        assertTrue(detectSearchQuery("What is happening in Ukraine?"))
+        assertTrue(detectSearchQuery("Weather in Tokyo today"))
+        assertTrue(detectSearchQuery("Who won the Champions League?"))
+        assertTrue(detectSearchQuery("Stock price of Apple"))
+        assertTrue(detectSearchQuery("Look up population of Germany"))
+    }
+
+    @Test
+    fun doesNotTriggerOnNormalPrompts() {
+        assertFalse(detectSearchQuery("Erkläre mir Quantencomputing"))
+        assertFalse(detectSearchQuery("Schreib mir ein Gedicht"))
+        assertFalse(detectSearchQuery("Was ist der Unterschied zwischen Java und Kotlin?"))
+        assertFalse(detectSearchQuery("Fasse diesen Text zusammen"))
+        assertFalse(detectSearchQuery("Hello"))
+    }
+
+    @Test
+    fun shortInputIsIgnored() {
+        assertFalse(detectSearchQuery("hi"))
+        assertFalse(detectSearchQuery(""))
+        assertFalse(detectSearchQuery("abc"))
+    }
+}