Add QR pairing (terminal QR, in-app scanner, iris://pair deep link)

app/shared/src/commonMain/kotlin/iris/IrisApp.kt

@@ -10,6 +10,7 @@ import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.key
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.ContentScale
@@ -26,6 +27,7 @@ import iris.ui.theme.IrisColors
 import iris.ui.theme.IrisTheme
 import iris.ui.theme.LocalUserTheme
 import iris.ui.theme.rememberBackgroundImage
+import iris.util.PairLink
 
 /**
  * Root composable shared by the Android and Desktop shells.
@@ -39,6 +41,7 @@ fun IrisApp(
     store: SecureStore,
     deepLinkChatId: String? = null,
     deepLinkThreadId: String? = null,
+    deepLinkPair: PairLink? = null,
 ) {
     val controller = remember(store) { IrisController(store) }
     DisposableEffect(controller) {
@@ -66,10 +69,11 @@ fun IrisApp(
         // untouched, so the UI keeps its proportions at any size.
         CompositionLocalProvider(
             LocalUserTheme provides theme,
-            LocalDensity provides Density(
-                density = baseDensity.density,
-                fontScale = baseDensity.fontScale * fontScale,
-            ),
+            LocalDensity provides
+                Density(
+                    density = baseDensity.density,
+                    fontScale = baseDensity.fontScale * fontScale,
+                ),
         ) {
             // The color goes through Surface's `color` parameter: a
             // Modifier.background on the Surface would be painted *under* the
@@ -95,20 +99,34 @@ fun IrisApp(
                         )
                     }
                     val s = state
+                    // QR pairing (docs/20): an iris://pair deep link prefills
+                    // the Connect screen, taking priority over stored creds.
+                    val pairUrl = deepLinkPair?.url ?: store.serverUrl
+                    val pairToken = deepLinkPair?.token ?: store.token
                     when (s) {
-                        GatewayClient.State.Disconnected ->
-                            ConnectScreen(controller, prefillUrl = store.serverUrl, prefillToken = store.token)
-                        is GatewayClient.State.AuthFailed ->
-                            ConnectScreen(
-                                controller,
-                                prefillUrl = store.serverUrl,
-                                prefillToken = store.token,
-                                initialError = "Pairing rejected: ${s.message}",
-                            )
+                        GatewayClient.State.Disconnected -> {
+                            key(deepLinkPair) {
+                                ConnectScreen(controller, prefillUrl = pairUrl, prefillToken = pairToken)
+                            }
+                        }
+
+                        is GatewayClient.State.AuthFailed -> {
+                            key(deepLinkPair) {
+                                ConnectScreen(
+                                    controller,
+                                    prefillUrl = pairUrl,
+                                    prefillToken = pairToken,
+                                    initialError = "Pairing rejected: ${s.message}",
+                                )
+                            }
+                        }
+
                         // Connecting / Reconnecting / Connected all render the chat; the header
                         // status bubble + connection banner show the link state
                         // without blocking the view (M7's full-screen spinner is gone).
-                        else -> ChatScreen(controller)
+                        else -> {
+                            ChatScreen(controller)
+                        }
                     }
                     // M9: full-screen HTML artifact preview (opened from an
                     // artifact card in the chat); covers everything while open.
@@ -117,4 +135,4 @@ fun IrisApp(
             }
         }
     }
-}
+}

app/shared/src/commonMain/kotlin/iris/data/ChatStore.kt

@@ -132,15 +132,16 @@ class ChatStore {
     var streamingEnabled: Boolean = true
 
     companion object {
-        const val DEFAULT_LANE = "android:default"
+        const val DEFAULT_LANE = "default"
 
         fun randomId(prefix: String): String = "${prefix}${Random.nextLong(1_000_000_000L, 9_999_999_999L)}"
     }
 
     // ── Lane helpers ──────────────────────────────────────────────────────
 
-    /** Lane key for a (chat, thread) pair. Uses `::` as the separator because
-     *  chat ids already contain a single `:` (e.g. `android:chan_1`). */
+    /** Lane key for a (chat, thread) pair. Uses `::` as the separator so a
+     *  thread lane can never collide with a chat id (chat ids are direct,
+     *  e.g. `chan_1`, and never contain `:`). */
     fun laneKey(
         chatId: String,
         threadId: String?,

app/shared/src/commonMain/kotlin/iris/data/SecureStore.kt

@@ -9,7 +9,7 @@ interface SecureStore {
     /** http(s)://host:port (legacy ws(s):// URLs are still accepted) */
     var serverUrl: String
 
-    /** ANDROID_TOKEN presented in the auth header. */
+    /** IRIS_TOKEN presented in the auth header. */
     var token: String
 
     /** Stable app-generated device id (persisted). */

app/shared/src/commonMain/kotlin/iris/net/GatewayClient.kt

@@ -33,7 +33,7 @@ import java.util.concurrent.TimeUnit
 import kotlin.random.Random
 
 /**
- * HTTP client for the hermes android gateway (docs/19).
+ * HTTP client for the hermes iris gateway (docs/19).
  *
  * HTTP is the only transport: send via `POST /v1/frame`, receive over SSE
  * `/v1/events` (long-poll fallback), media via `POST/GET /v1/media`.

app/shared/src/commonMain/kotlin/iris/platform/PlatformQr.kt

@@ -0,0 +1,13 @@
+package iris.platform
+
+import androidx.compose.runtime.Composable
+
+/**
+ * A "Scan QR" button that launches the platform QR scanner and delivers the
+ * scanned text (or null if the user cancelled) to [onResult] (docs/20).
+ *
+ * Android: opens [QrScanActivity] (CameraX + ML Kit). Desktop: renders nothing
+ * (the Connect screen hides it there).
+ */
+@Composable
+expect fun QrScanButton(onResult: (String?) -> Unit)

app/shared/src/commonMain/kotlin/iris/state/IrisController.kt

@@ -134,7 +134,7 @@ class IrisController(
     }
 
     /** Home channel id (from hello.ack; default until then). */
-    private val _homeChannel = MutableStateFlow("android:default")
+    private val _homeChannel = MutableStateFlow("default")
     val homeChannel: StateFlow<String> = _homeChannel.asStateFlow()
 
     /** Lanes whose full history has been loaded this session (in-memory; reset
@@ -408,7 +408,7 @@ class IrisController(
     ) {
         if (isAppForeground()) return
         if (text.isBlank()) return
-        val id = chatId ?: "android:default"
+        val id = chatId ?: "default"
         val chatName = channels.byId(id)?.name
         postSystemNotification(id, chatName, chatName ?: "Iris", preview(text), threadId)
     }

app/shared/src/commonMain/kotlin/iris/ui/screens/ChatScreen.kt

@@ -1314,7 +1314,7 @@ private fun SystemMessage(msg: MessageItem) {
 
 /** M7: header title pill — channel avatar + channel name. Automation
  *  channels show their chat_id as a subtitle (tap the pill to copy it) so
- *  the user can target them for cron delivery (`deliver="android:<chat_id>"`)
+ *  the user can target them for cron delivery (`deliver="iris:<chat_id>"`)
  *  without asking the agent which channel is in use. */
 @Composable
 private fun TitlePill(

app/shared/src/commonMain/kotlin/iris/ui/screens/ConnectScreen.kt

@@ -27,8 +27,11 @@ import androidx.compose.ui.draw.clip
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.text.input.PasswordVisualTransformation
 import androidx.compose.ui.unit.dp
+import iris.platform.QrScanButton
+import iris.platform.isDesktop
 import iris.state.IrisController
 import iris.ui.theme.IrisColors
+import iris.util.PairLink
 import kotlinx.coroutines.launch
 
 /**
@@ -91,11 +94,25 @@ fun ConnectScreen(
                 value = token,
                 onValueChange = { token = it },
                 label = { Text("Pairing token") },
-                placeholder = { Text("ANDROID_TOKEN (64 hex)") },
+                placeholder = { Text("IRIS_TOKEN (64 hex)") },
                 singleLine = true,
                 visualTransformation = PasswordVisualTransformation(),
                 modifier = Modifier.fillMaxWidth(),
             )
+            if (!isDesktop) {
+                Spacer(modifier = Modifier.height(12.dp))
+                QrScanButton { raw ->
+                    if (raw != null) {
+                        val link = PairLink.parse(raw)
+                        if (link != null) {
+                            url = link.url
+                            token = link.token
+                        } else {
+                            error = "Couldn't read that QR code."
+                        }
+                    }
+                }
+            }
             Spacer(modifier = Modifier.height(24.dp))
 
             Button(
@@ -129,7 +146,7 @@ fun ConnectScreen(
 
         Spacer(modifier = Modifier.height(24.dp))
         Text(
-            "Find the token in ~/.hermes/.env (ANDROID_TOKEN) or run\n" +
+            "Find the token in ~/.hermes/.env (IRIS_TOKEN) or run\n" +
                 "hermes gateway setup on the gateway host.",
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,

app/shared/src/commonMain/kotlin/iris/util/PairLink.kt

@@ -0,0 +1,97 @@
+package iris.util
+
+/**
+ * A parsed `iris://pair` deep link: the gateway URL to connect to plus the
+ * one-time pairing token. Produced by [PairLink.parse] from a scanned QR or a
+ * tapped `iris://pair` link (docs/20).
+ */
+data class PairLink(
+    val url: String,
+    val token: String,
+) {
+    companion object {
+        /** Default gateway HTTP port (docs/19). */
+        const val DEFAULT_PORT = 8791
+
+        /**
+         * Parse a pairing link into a [PairLink], or return null on any
+         * malformation.
+         *
+         * - scheme must be `iris` (case-insensitive); the URI host must be `pair`.
+         * - required query params: `host` (non-empty) and `token` (non-empty).
+         * - `port` defaults to [DEFAULT_PORT]; must be 1–65535 when present.
+         * - `secure` defaults to `0`; `1` selects https.
+         * - `host`/`token` are percent-decoded (the Python side `quote()`s them).
+         */
+        fun parse(raw: String): PairLink? {
+            val qIdx = raw.indexOf('?')
+            val authority = if (qIdx >= 0) raw.substring(0, qIdx) else raw
+            val query = if (qIdx >= 0) raw.substring(qIdx + 1) else ""
+
+            // authority is "iris://pair": scheme, then "://", then the URI host.
+            val sep = authority.indexOf("://")
+            if (sep <= 0) return null
+            val scheme = authority.substring(0, sep)
+            val uriHost = authority.substring(sep + 3)
+            if (scheme.lowercase() != "iris") return null
+            if (uriHost.lowercase() != "pair") return null
+
+            val params = parseQuery(query)
+            val host = params["host"]?.let { percentDecode(it) }?.trim().orEmpty()
+            val token = params["token"]?.let { percentDecode(it) }?.trim().orEmpty()
+            if (host.isEmpty() || token.isEmpty()) return null
+
+            val portRaw = params["port"]
+            val port =
+                if (portRaw.isNullOrEmpty()) {
+                    DEFAULT_PORT
+                } else {
+                    portRaw.toIntOrNull() ?: return null
+                }
+            if (port !in 1..65535) return null
+            val secure = params["secure"]?.toIntOrNull() ?: 0
+            val urlScheme = if (secure == 1) "https" else "http"
+            return PairLink("$urlScheme://$host:$port", token)
+        }
+
+        /** Split a `k=v&k=v` query string into a map (values may be empty). */
+        private fun parseQuery(query: String): Map<String, String> {
+            if (query.isEmpty()) return emptyMap()
+            val map = LinkedHashMap<String, String>()
+            for (pair in query.split('&')) {
+                if (pair.isEmpty()) continue
+                val eq = pair.indexOf('=')
+                if (eq < 0) {
+                    map[pair] = ""
+                } else {
+                    map[pair.substring(0, eq)] = pair.substring(eq + 1)
+                }
+            }
+            return map
+        }
+
+        /**
+         * Percent-decode `%XX` sequences (byte-wise; pairing payloads are ASCII
+         * — IPs and 64-hex tokens). A `%` that does not start a valid
+         * two-hex-digit escape is kept literally.
+         */
+        private fun percentDecode(s: String): String {
+            val sb = StringBuilder(s.length)
+            var i = 0
+            while (i < s.length) {
+                val c = s[i]
+                if (c == '%' && i + 2 < s.length) {
+                    val code = s.substring(i + 1, i + 3).toIntOrNull(16)
+                    if (code != null) {
+                        sb.append(code.toChar())
+                        i += 3
+                        continue
+                    }
+                }
+                sb.append(c)
+                i++
+            }
+            return sb.toString()
+        }
+    }
+}