Phase 1 app: session list, session screen, spawn, QR enrollment over pinned TLS

Compose app mirroring local-updater's stack (single :androidApp module,
pinned CA, HttpURLConnection transport) plus what this app needs on top:
a bearer token sealed with an Android Keystore AES-GCM key, an
aiapp://enroll intent filter so scanning the server's terminal QR with
the stock camera enrolls the phone with no QR library, an SSE client
that resumes by transcript cursor, and a transcript renderer folding the
common event model into user bubbles, streaming text, collapsible tool
cards, and answerable question cards.

Verified on the tdep emulator against the real server: enrollment deep
link, list, spawn, streamed echo turn, question answer round trip, tool
card expansion, adjustResize keyboard behavior. Build is warning-clean
(compose.* accessors replaced with direct dependencies).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017xn8nHw1tw1R6PtiY1eEtw

app/androidApp/src/main/kotlin/com/example/aiapp/SettingsScreen.kt

@@ -0,0 +1,110 @@
+package com.example.aiapp
+
+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
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+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.platform.LocalContext
+import androidx.compose.ui.unit.dp
+
+/**
+ * Server address and token. The normal path is scanning the server's
+ * terminal QR (which lands in MainActivity and never shows this screen);
+ * these fields are the fallback for typing the same three values by hand.
+ * [onBack] is null on first run, when there is nothing to go back to.
+ */
+@Composable
+fun SettingsScreen(
+    existing: ServerSettings?,
+    onSaved: (ServerSettings) -> Unit,
+    onBack: (() -> Unit)?,
+) {
+    val context = LocalContext.current
+    var host by remember { mutableStateOf(existing?.host ?: "10.66.0.1") }
+    var port by remember { mutableStateOf((existing?.port ?: 8443).toString()) }
+    // Never pre-filled from the stored token: this screen shouldn't be a
+    // way to read the credential back off the device.
+    var token by remember { mutableStateOf("") }
+    var error by remember { mutableStateOf<String?>(null) }
+
+    Column(Modifier.fillMaxSize().padding(16.dp)) {
+        Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
+            Text(
+                "Server",
+                style = MaterialTheme.typography.headlineSmall,
+                modifier = Modifier.weight(1f),
+            )
+            if (onBack != null) {
+                TextButton(onClick = onBack) { Text("Back") }
+            }
+        }
+        Spacer(Modifier.height(8.dp))
+        Text(
+            "The easy way: run ai-server on the backend and scan the QR it prints " +
+                "with the phone's camera. Or type the same values here.",
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+        Spacer(Modifier.height(16.dp))
+
+        OutlinedTextField(
+            value = host,
+            onValueChange = { host = it },
+            label = { Text("Host") },
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth(),
+        )
+        Spacer(Modifier.height(8.dp))
+        OutlinedTextField(
+            value = port,
+            onValueChange = { port = it },
+            label = { Text("Port") },
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth(),
+        )
+        Spacer(Modifier.height(8.dp))
+        OutlinedTextField(
+            value = token,
+            onValueChange = { token = it },
+            label = { Text(if (existing != null) "Token (unchanged if left blank)" else "Token") },
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth(),
+        )
+        Spacer(Modifier.height(24.dp))
+
+        error?.let {
+            Text(it, color = MaterialTheme.colorScheme.error)
+            Spacer(Modifier.height(8.dp))
+        }
+
+        Button(onClick = {
+            val portNumber = port.trim().toIntOrNull()
+            val effectiveToken = token.trim().ifEmpty { existing?.token ?: "" }
+            when {
+                host.isBlank() -> error = "Host is required"
+                portNumber == null || portNumber !in 1..65535 -> error = "Port must be 1-65535"
+                effectiveToken.isEmpty() -> error = "Token is required -- scan the server's QR or paste it"
+                else -> {
+                    val settings = ServerSettings(host.trim(), portNumber, effectiveToken)
+                    saveServerSettings(context, settings)
+                    onSaved(settings)
+                }
+            }
+        }) { Text("Save") }
+    }
+}