feat(aiturk): hide what the paired IDE cannot serve, plain error sentences, reconnect on return

When paired with AITURK IDE:
- an "unknown method" (-32601) answer and the proxy's 403/route-404 are shown
  as plain sentences, never as raw JsonRpcError text; a method the IDE does
  not have is not sent again on the same socket
- Account connectors, Vault, Keys and Files are hidden (the IDE has no
  connectors.* / vault.* and its phone proxy refuses /api/env and /api/files)
- an idle-closed chat socket is reopened when the app returns to the
  foreground; idle tunnel connections are dropped on a network change
- an unsaved chat no longer polls /api/sessions/<id>
- the pairing screen shows the app version

A plain Hermes connection is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B8ppceaR5s6cvMnm7uGRnf

app/src/main/java/com/m57/hermescontrol/ui/aiturkpair/AiturkFeatureGate.kt

@@ -0,0 +1,60 @@
+package com.m57.hermescontrol.ui.aiturkpair
+
+import androidx.annotation.StringRes
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Computer
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.res.stringResource
+import androidx.navigation3.runtime.NavKey
+import com.m57.hermescontrol.AccountConnectorsScreen
+import com.m57.hermescontrol.FilesScreen
+import com.m57.hermescontrol.KeysScreen
+import com.m57.hermescontrol.R
+import com.m57.hermescontrol.SettingsVault
+import com.m57.hermescontrol.data.aiturk.AiturkCompat
+import com.m57.hermescontrol.ui.common.EmptyState
+import com.m57.hermescontrol.ui.common.HermesScaffold
+import com.m57.hermescontrol.ui.common.NavIcon
+
+/**
+ * Screens a paired AITURK IDE cannot serve, hidden from the drawer and the
+ * settings list while that pairing is the active connection:
+ *
+ *  - Account connectors, Credential vault: the IDE's agent has no
+ *    `connectors.*` / `vault.*` methods;
+ *  - Keys, Files: the IDE's phone proxy refuses `/api/env` and `/api/files`
+ *    on purpose (secrets and the computer's files stay on the computer).
+ *
+ * A plain Hermes dashboard connection shows everything, as upstream does.
+ */
+object AiturkFeatureGate {
+    val HIDDEN_WHEN_LINKED: Set<NavKey> = setOf(AccountConnectorsScreen, KeysScreen, FilesScreen, SettingsVault)
+
+    fun shows(
+        key: NavKey,
+        linked: Boolean = AiturkCompat.isLinked(),
+    ): Boolean = !(linked && key in HIDDEN_WHEN_LINKED)
+}
+
+/** Shown instead of a hidden screen that is still reached (restored back stack, shortcut). */
+@Composable
+fun AiturkUnavailableScreen(
+    @StringRes titleRes: Int,
+    onOpenDrawer: (() -> Unit)?,
+) {
+    HermesScaffold(
+        title = { Text(stringResource(titleRes)) },
+        navigationIcon = onOpenDrawer?.let { NavIcon.Menu(it) },
+    ) { padding ->
+        EmptyState(
+            title = stringResource(R.string.aiturk_feature_unavailable),
+            subtitle = stringResource(R.string.aiturk_feature_unavailable_hint),
+            icon = Icons.Filled.Computer,
+            modifier = Modifier.padding(padding).testTag("aiturk_unavailable"),
+        )
+    }
+}

app/src/main/java/com/m57/hermescontrol/ui/aiturkpair/AiturkPairScreen.kt

@@ -43,6 +43,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.font.FontFamily
@@ -61,6 +62,7 @@ import androidx.lifecycle.viewmodel.compose.viewModel
 import com.journeyapps.barcodescanner.ScanContract
 import com.journeyapps.barcodescanner.ScanOptions
 import com.m57.hermescontrol.R
+import com.m57.hermescontrol.data.aiturk.AiturkCompat
 import com.m57.hermescontrol.data.aiturk.AiturkPairing
 import com.m57.hermescontrol.data.remote.requiresLocalNetworkPermission
 
@@ -286,6 +288,15 @@ fun AiturkPairScreen(
             TextButton(onClick = onBack, enabled = !state.busy) {
                 Text(stringResource(R.string.aiturk_pair_back))
             }
+
+            // So the user can tell which build is installed when support asks.
+            Text(
+                text = stringResource(R.string.aiturk_app_version, AiturkCompat.versionLabel()),
+                modifier = Modifier.testTag("aiturk_app_version"),
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                style = MaterialTheme.typography.labelSmall,
+                textAlign = TextAlign.Center,
+            )
         }
     }
 }