feat: add ConnectionStatusAction component for real-time server health monitoring in UI screens

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/components/ConnectionStatus.kt

@@ -0,0 +1,124 @@
+package com.collabtable.app.ui.components
+
+import android.net.Uri
+import android.os.Build
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+import com.collabtable.app.data.preferences.PreferencesManager
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import java.util.concurrent.TimeUnit
+
+private val statusClient: OkHttpClient =
+    OkHttpClient.Builder()
+        .connectTimeout(5, TimeUnit.SECONDS)
+        .readTimeout(5, TimeUnit.SECONDS)
+        .build()
+
+private fun isEmulator(): Boolean {
+    val fp = Build.FINGERPRINT.lowercase()
+    val model = Build.MODEL.lowercase()
+    val brand = Build.BRAND.lowercase()
+    val device = Build.DEVICE.lowercase()
+    val product = Build.PRODUCT.lowercase()
+    return fp.contains("generic") || fp.contains("emulator") ||
+        model.contains("google_sdk") || model.contains("emulator") || model.contains("android sdk built for") ||
+        brand.startsWith("generic") || device.startsWith("generic") || product.contains("sdk")
+}
+
+private fun toHealthUrl(rawApiUrl: String): String {
+    // Ensure we hit the unauthenticated /health endpoint and remap localhost on emulator
+    return try {
+        val uri = Uri.parse(rawApiUrl)
+        val host = uri.host?.lowercase()
+        val needsRemap = isEmulator() && (host == "localhost" || host == "127.0.0.1" || host == "host.docker.internal")
+        val scheme = uri.scheme ?: "http"
+        val portPart = if (uri.port != -1) ":${uri.port}" else ""
+        val base = if (needsRemap) "$scheme://10.0.2.2$portPart" else "$scheme://${uri.host ?: ""}$portPart"
+        val path = (uri.encodedPath ?: "/").trimEnd('/')
+        val healthPath = if (path.endsWith("/api") || path.endsWith("/api/")) "/health" else "/health"
+        base + healthPath
+    } catch (e: Exception) {
+        rawApiUrl.replace("/api/", "/health").replace("/api", "/health")
+    }
+}
+
+@Composable
+fun ConnectionStatusAction(
+    prefs: PreferencesManager,
+    modifier: Modifier = Modifier,
+    showLatency: Boolean = true,
+) {
+    var ok by remember { mutableStateOf<Boolean?>(null) }
+    var latencyMs by remember { mutableStateOf<Long?>(null) }
+
+    val intervalMs by prefs.syncPollIntervalMs.collectAsState()
+
+    // Periodic health check aligned to polling interval
+    LaunchedEffect(intervalMs) {
+        while (true) {
+            try {
+                val healthUrl = toHealthUrl(prefs.getServerUrl())
+                val req = Request.Builder().url(healthUrl).get().build()
+                val start = System.nanoTime()
+                val resp = withContext(Dispatchers.IO) { statusClient.newCall(req).execute() }
+                val tookMs = (System.nanoTime() - start) / 1_000_000
+                if (resp.isSuccessful) {
+                    ok = true
+                    latencyMs = tookMs
+                } else {
+                    ok = false
+                }
+                resp.close()
+            } catch (e: Exception) {
+                ok = false
+            }
+            delay(intervalMs)
+        }
+    }
+
+    val dotColor: Color = when (ok) {
+        true -> Color(0xFF2E7D32) // green
+        false -> MaterialTheme.colorScheme.error
+        null -> MaterialTheme.colorScheme.onSurfaceVariant
+    }
+
+    Row(
+        modifier = modifier,
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(6.dp),
+    ) {
+        if (showLatency && ok == true && latencyMs != null) {
+            Text(
+                text = "${latencyMs} ms",
+                style = MaterialTheme.typography.labelSmall,
+                color = MaterialTheme.colorScheme.onPrimaryContainer,
+            )
+        }
+        Box(
+            modifier =
+                Modifier
+                    .size(12.dp)
+                    .background(dotColor, shape = androidx.compose.foundation.shape.CircleShape),
+        )
+    }
+}

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/screens/ListDetailScreen.kt

@@ -75,6 +75,8 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
 import com.collabtable.app.R
+import com.collabtable.app.data.preferences.PreferencesManager
+import com.collabtable.app.ui.components.ConnectionStatusAction
 import com.collabtable.app.data.database.CollabTableDatabase
 import com.collabtable.app.data.model.Field
 import com.collabtable.app.data.model.ItemWithValues
@@ -200,6 +202,9 @@ fun ListDetailScreen(
                     }
                 },
                 actions = {
+                    val context = LocalContext.current
+                    val prefs = remember { PreferencesManager.getInstance(context) }
+                    ConnectionStatusAction(prefs = prefs)
                     IconButton(onClick = { showManageColumnsDialog = true }) {
                         Icon(Icons.Default.Settings, contentDescription = "Manage Columns")
                     }

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/screens/ListsScreen.kt

@@ -55,6 +55,7 @@ import com.collabtable.app.R
 import com.collabtable.app.data.database.CollabTableDatabase
 import com.collabtable.app.data.model.CollabList
 import com.collabtable.app.data.preferences.PreferencesManager
+import com.collabtable.app.ui.components.ConnectionStatusAction
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import org.burnoutcrew.reorderable.ReorderableItem
@@ -86,6 +87,9 @@ fun ListsScreen(
             TopAppBar(
                 title = { Text(stringResource(R.string.lists)) },
                 actions = {
+                    val context = LocalContext.current
+                    val prefsLocal = remember { PreferencesManager.getInstance(context) }
+                    ConnectionStatusAction(prefs = prefsLocal)
                     IconButton(onClick = { viewModel.manualSync() }) {
                         Icon(Icons.Default.Refresh, contentDescription = "Sync")
                     }

CollabTableAndroid/app/src/main/java/com/collabtable/app/ui/screens/SettingsScreen.kt

@@ -44,6 +44,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.graphics.Color
+import com.collabtable.app.ui.components.ConnectionStatusAction
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
@@ -142,32 +143,7 @@ fun SettingsScreen(
                     }
                 },
                 actions = {
-                    // Connection status dot: green=ok, red=error, gray=unknown
-                    val dotColor = when (testOk) {
-                        true -> Color(0xFF2E7D32)
-                        false -> MaterialTheme.colorScheme.error
-                        null -> MaterialTheme.colorScheme.onSurfaceVariant
-                    }
-                    Row(
-                        modifier = Modifier.padding(end = 8.dp),
-                        verticalAlignment = Alignment.CenterVertically,
-                        horizontalArrangement = Arrangement.spacedBy(6.dp),
-                    ) {
-                        if (lastLatencyMs != null && testOk == true) {
-                            Text(
-                                text = "${'$'}{lastLatencyMs} ms",
-                                style = MaterialTheme.typography.labelSmall,
-                                color = MaterialTheme.colorScheme.onPrimaryContainer,
-                            )
-                        }
-                        Box(
-                            modifier =
-                                Modifier
-                                    .size(12.dp)
-                                    .clip(androidx.compose.foundation.shape.CircleShape)
-                                    .background(dotColor),
-                        )
-                    }
+                    ConnectionStatusAction(prefs = preferencesManager)
                 },
                 colors =
                     TopAppBarDefaults.topAppBarColors(