refactor: remove device Pairing feature entirely (issue #645) (#650)

* refactor: remove device Pairing feature entirely (issue #645)

- Delete Pairing.kt model + pairing API endpoints (get/approve/revoke/clear)
- Delete PairingScreen/PairingViewModel + PairingCodeEntryScreen/ViewModel
- Remove NavKeys, ScreenRegistry drawer entry, Navigation.kt entry + Landing pairing button
- Remove pairing string resources (en + ko); keep connect_* config-parse strings
- Keep Telegram onboarding pairing_id flow (separate concept, per issue)
- Fix related doc comments + remaining test reference

* test: fix racy CONNECTED read in gated-mode WS test (issue #635 test)

testGatedMode_attemptsTicketFetchWithoutBareCookie asserted CONNECTED
immediately after the server-side onOpen latch fired, racing the client
handshake (WsListenerImpl sets CONNECTED on receipt of the 101). Await the
real status transition via connectionStatus.first{==CONNECTED} like the
other connect tests do. No product behavior changed.

---------

Co-authored-by: M57 <Hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ScreenRegistry.kt

@@ -12,7 +12,6 @@ import androidx.compose.material.icons.filled.Build
 import androidx.compose.material.icons.filled.Cloud
 import androidx.compose.material.icons.filled.Code
 import androidx.compose.material.icons.filled.Dashboard
-import androidx.compose.material.icons.filled.Devices
 import androidx.compose.material.icons.filled.Extension
 import androidx.compose.material.icons.filled.History
 import androidx.compose.material.icons.filled.HistoryEdu
@@ -39,7 +38,6 @@ import com.m57.hermescontrol.ui.keys.KeysScreen as KeysScreenContent
 import com.m57.hermescontrol.ui.logs.LogsScreen as LogsScreenContent
 import com.m57.hermescontrol.ui.mcp.McpServersScreen as McpServersScreenContent
 import com.m57.hermescontrol.ui.model.ModelScreen as ModelScreenContent
-import com.m57.hermescontrol.ui.pairing.PairingScreen as PairingScreenContent
 import com.m57.hermescontrol.ui.plugins.PluginsScreen as PluginsScreenContent
 import com.m57.hermescontrol.ui.process.ProcessesScreen as ProcessesScreenContent
 import com.m57.hermescontrol.ui.profiles.ProfilesScreen as ProfilesScreenContent
@@ -143,12 +141,6 @@ object ScreenRegistry {
                 Icons.Filled.Psychology,
                 DrawerSection.CONFIGURE,
             ) { sessionId, openDrawer -> ModelScreenContent(onOpenDrawer = openDrawer) },
-            ScreenDefinition(
-                PairingScreen,
-                R.string.screen_pairing,
-                Icons.Filled.Devices,
-                DrawerSection.CONFIGURE,
-            ) { sessionId, openDrawer -> PairingScreenContent(onOpenDrawer = openDrawer) },
             ScreenDefinition(
                 KeysScreen,
                 R.string.screen_keys,