refactor: merge Test tab into Settings, 3 tabs total

- Settings tab now has credential fields + network test (Test Pi, Test Server)
- Removed standalone Test tab
- Bottom nav: Dashcam, Downloads, Settings

android/app/src/main/java/com/yarisobd/app/MainActivity.kt

@@ -83,19 +83,15 @@ fun YarisMainScreen(client: OkHttpClient) {
                 NavigationBarItem(
                     selected = selectedTab == 1,
                     onClick = { selectedTab = 1 },
-                    icon = { Text("�") },
+                    icon = { Text(".") },
                     label = { Text("Downloads") }
                 )
                 NavigationBarItem(
                     selected = selectedTab == 2,
-                    onClick = { selectedTab = 2 },                    icon = { Text("⚙️") },
+                    onClick = { selectedTab = 2 },
+                    icon = { Text(".") },
                     label = { Text("Settings") }
                 )
-                NavigationBarItem(
-                    selected = selectedTab == 3,
-                    onClick = { selectedTab = 3 },                    icon = { Text("�🔌") },
-                    label = { Text("Test") }
-                )
             }
         }
     ) { padding ->
@@ -124,11 +120,7 @@ fun YarisMainScreen(client: OkHttpClient) {
                     onCancelUpload = { dashcamVm.cancelUpload(it) },
                     onRefresh = { dashcamVm.scanDownloads() },
                 )
-                2 -> SettingsScreen()
+                2 -> SettingsScreen(client = client)
-                3 -> DualNetworkTestScreen(
-                    piClient = client,
-                    serverClient = client,
-                )
             }
         }
     }

android/app/src/main/java/com/yarisobd/app/SettingsScreen.kt

@@ -1,6 +1,7 @@
 package com.yarisobd.app
 
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
@@ -9,6 +10,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.Button
+import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.MaterialTheme
@@ -18,21 +20,32 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
 import com.yarisobd.app.data.CredentialStore
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import okhttp3.OkHttpClient
+import okhttp3.Request
 
 @Composable
-fun SettingsScreen() {
+fun SettingsScreen(client: OkHttpClient) {
     val context = LocalContext.current
+    val scope = rememberCoroutineScope()
     var serverUrl by remember { mutableStateOf(CredentialStore.getServerUrl(context)) }
     var deviceName by remember { mutableStateOf(CredentialStore.getDeviceName(context)) }
     var apiKey by remember { mutableStateOf("") }
     var saved by remember { mutableStateOf(false) }
     val configured = CredentialStore.isConfigured(context)
 
+    // Network test state
+    var piResult by remember { mutableStateOf<String?>(null) }
+    var serverResult by remember { mutableStateOf<String?>(null) }
+
     Column(
         modifier = Modifier.fillMaxSize().verticalScroll(rememberScrollState()).padding(16.dp)
     ) {
@@ -82,8 +95,46 @@ fun SettingsScreen() {
                         saved = true
                     },
                     modifier = Modifier.fillMaxWidth()
-                ) { Text(if (saved) "✓ Saved — restart app to apply" else "Save") }
+                ) { Text(if (saved) "✓ Saved" else "Save") }
+            }
+        }
+
+        Spacer(Modifier.height(16.dp))
+
+        // Network test
+        Card(
+            modifier = Modifier.fillMaxWidth(),
+            colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh)
+        ) {
+            Column(modifier = Modifier.padding(16.dp)) {
+                Text("Network Test", style = MaterialTheme.typography.titleMedium)
+                Spacer(Modifier.height(8.dp))
+                Row { Button(onClick = {
+                    piResult = null
+                    scope.launch { piResult = testPi(client) }
+                }, modifier = Modifier.weight(1f)) { Text("Test Pi") } }
+                piResult?.let { Text(it, style = MaterialTheme.typography.bodySmall, color = if (it.startsWith("✓")) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.error, modifier = Modifier.padding(top = 4.dp)) }
+                Spacer(Modifier.height(8.dp))
+                Row { Button(onClick = {
+                    serverResult = null
+                    scope.launch { serverResult = testServer(client) }
+                }, modifier = Modifier.weight(1f), colors = ButtonDefaults.buttonColors(containerColor = MaterialTheme.colorScheme.secondary)) { Text("Test Server") } }
+                serverResult?.let { Text(it, style = MaterialTheme.typography.bodySmall, color = if (it.startsWith("✓")) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.error, modifier = Modifier.padding(top = 4.dp)) }
             }
         }
     }
 }
+
+private suspend fun testPi(client: OkHttpClient): String = withContext(Dispatchers.IO) {
+    try {
+        val res = client.newCall(Request.Builder().url("http://10.42.0.1/api/gps/status").get().build()).execute()
+        if (res.isSuccessful) "✓ Pi OK (${res.code})" else "✗ Pi HTTP ${res.code}"
+    } catch (e: Exception) { "✗ ${e.message}" }
+}
+
+private suspend fun testServer(client: OkHttpClient): String = withContext(Dispatchers.IO) {
+    try {
+        val res = client.newCall(Request.Builder().url("https://yaris.ceaf.dev/health").get().build()).execute()
+        if (res.isSuccessful) "✓ Server OK (${res.code})" else "✗ Server HTTP ${res.code}"
+    } catch (e: Exception) { "✗ ${e.message}" }
+}