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/ui/landing/LandingScreen.kt

@@ -16,7 +16,6 @@ import androidx.compose.material.icons.filled.Bolt
 import androidx.compose.material3.Button
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
@@ -31,7 +30,6 @@ import com.m57.hermescontrol.R
 @Composable
 fun LandingScreen(
     onAuthLogin: () -> Unit,
-    onPairingLogin: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
     Box(
@@ -98,16 +96,6 @@ fun LandingScreen(
                     style = MaterialTheme.typography.titleMedium,
                 )
             }
-
-            OutlinedButton(
-                onClick = onPairingLogin,
-                modifier = Modifier.fillMaxWidth().height(56.dp),
-            ) {
-                Text(
-                    text = stringResource(R.string.landing_action_pairing_login),
-                    style = MaterialTheme.typography.titleMedium,
-                )
-            }
         }
     }
 }