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(
             }
         }
     }
-}
+}