feat: surface /api/status memory+disk pressure on connect/status screens (#903) (#908)

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/common/PressureBanner.kt

@@ -0,0 +1,133 @@
+package com.m57.hermescontrol.ui.common
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Warning
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import com.m57.hermescontrol.R
+import com.m57.hermescontrol.data.model.DiskPressureStatus
+import com.m57.hermescontrol.data.model.MemoryPressureStatus
+import com.m57.hermescontrol.theme.LocalHermesStatusColors
+import com.m57.hermescontrol.theme.onColorFor
+
+/**
+ * Worst-first severity of the host-health advisory (mirrors the desktop
+ * `MemoryPressureBanner` trigger order, issue #903): disk critical beats
+ * memory critical (imminent data loss beats imminent restart), and a
+ * suspected-OOM restart is a post-mortem that beats plain elevated states.
+ */
+enum class PressureTrigger {
+    DISK_CRITICAL,
+    MEMORY_CRITICAL,
+    OOM_RESTART,
+    DISK_ELEVATED,
+    MEMORY_ELEVATED,
+}
+
+/**
+ * Picks the advisory to surface from the `/api/status` memory/disk blocks.
+ * Returns `null` when there is nothing to warn about. `unknown` pressure is
+ * absence of evidence, not recovery — it never triggers (and never clears)
+ * a banner, same as the desktop banner.
+ */
+internal fun selectPressureTrigger(
+    memory: MemoryPressureStatus?,
+    disk: DiskPressureStatus?,
+): PressureTrigger? =
+    when {
+        disk?.pressure == "critical" -> PressureTrigger.DISK_CRITICAL
+        memory?.pressure == "critical" -> PressureTrigger.MEMORY_CRITICAL
+        memory?.last_boot_suspected_oom == true -> PressureTrigger.OOM_RESTART
+        disk?.pressure == "elevated" -> PressureTrigger.DISK_ELEVATED
+        memory?.pressure == "elevated" -> PressureTrigger.MEMORY_ELEVATED
+        else -> null
+    }
+
+/**
+ * Small advisory banner for host resource trouble (issue #903): renders when
+ * the backend's `/api/status` reports memory/disk pressure, so an OOM-thrashing
+ * or disk-full host explains itself instead of looking like a dead agent.
+ * Advisory only — it never gates anything and never blocks the UI.
+ */
+@Composable
+fun PressureBanner(
+    memory: MemoryPressureStatus?,
+    disk: DiskPressureStatus?,
+    modifier: Modifier = Modifier,
+) {
+    val trigger = selectPressureTrigger(memory, disk) ?: return
+    val statusColors = LocalHermesStatusColors.current
+    val critical =
+        trigger == PressureTrigger.DISK_CRITICAL ||
+            trigger == PressureTrigger.MEMORY_CRITICAL
+    val bgColor =
+        if (critical) {
+            statusColors.errorContainer
+        } else {
+            statusColors.warningContainer
+        }
+    val fgColor = onColorFor(bgColor)
+
+    val message =
+        when (trigger) {
+            PressureTrigger.DISK_CRITICAL ->
+                stringResource(R.string.pressure_banner_disk_critical) +
+                    diskFreeSuffix(disk)
+
+            PressureTrigger.DISK_ELEVATED ->
+                stringResource(R.string.pressure_banner_disk_elevated) +
+                    diskFreeSuffix(disk)
+
+            PressureTrigger.MEMORY_CRITICAL ->
+                stringResource(R.string.pressure_banner_memory_critical)
+
+            PressureTrigger.OOM_RESTART ->
+                stringResource(R.string.pressure_banner_memory_oom)
+
+            PressureTrigger.MEMORY_ELEVATED ->
+                stringResource(R.string.pressure_banner_memory_elevated)
+        }
+
+    Surface(
+        modifier = modifier.fillMaxWidth(),
+        shape = MaterialTheme.shapes.medium,
+        color = bgColor,
+    ) {
+        Row(
+            modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            Icon(
+                imageVector = Icons.Filled.Warning,
+                contentDescription = null,
+                tint = fgColor,
+                modifier = Modifier.size(16.dp),
+            )
+            Text(
+                text = message,
+                style = MaterialTheme.typography.bodySmall,
+                color = fgColor,
+                modifier = Modifier.weight(1f),
+            )
+        }
+    }
+}
+
+@Composable
+private fun diskFreeSuffix(disk: DiskPressureStatus?): String {
+    val freeMb = disk?.free_mb ?: return ""
+    return stringResource(R.string.pressure_banner_disk_free_suffix, freeMb)
+}