refactor(tui): extract selectedPendingApproval() extension and unify call sites

Add TuiState.selectedPendingApproval() extension and replace the three
inline session-lookup expressions in InputReducer and RouterPanel with it.

apps/tui/src/main/kotlin/com/correx/apps/tui/components/RouterPanel.kt

@@ -1,6 +1,7 @@
 package com.correx.apps.tui.components
 
 import com.correx.apps.tui.state.TuiState
+import com.correx.apps.tui.state.selectedPendingApproval
 import dev.tamboui.style.Style
 import dev.tamboui.text.Line
 import dev.tamboui.text.Span
@@ -23,7 +24,7 @@ fun routerPanelWidget(state: TuiState): Paragraph {
         }
     }
 
-    val activeApproval = state.sessions.sessions.find { it.id == state.sessions.selectedId }?.pendingApproval
+    val activeApproval = state.selectedPendingApproval()
     val overlayLines: List<Line> = when {
         state.approvalOverlayVisible && activeApproval != null -> {
             buildList {

apps/tui/src/main/kotlin/com/correx/apps/tui/reducer/InputReducer.kt

@@ -5,6 +5,7 @@ import com.correx.apps.server.protocol.ClientMessage
 import com.correx.apps.tui.input.Action
 import com.correx.apps.tui.state.InputMode
 import com.correx.apps.tui.state.TuiState
+import com.correx.apps.tui.state.selectedPendingApproval
 import com.correx.core.events.types.ApprovalRequestId
 
 object InputReducer {
@@ -25,7 +26,7 @@ object InputReducer {
 
         is Action.OpenNewSessionPrompt -> state.copy(inputMode = InputMode.ROUTER, inputBuffer = "") to emptyList()
         is Action.OpenSteeringPrompt -> {
-            val active = state.sessions.sessions.find { it.id == state.sessions.selectedId }?.pendingApproval
+            val active = state.selectedPendingApproval()
             if (active != null) {
                 state.copy(inputMode = InputMode.STEER, inputBuffer = "") to emptyList()
             } else {
@@ -52,7 +53,7 @@ object InputReducer {
 
             InputMode.STEER -> {
                 val text = state.inputBuffer.trim()
-                val active = state.sessions.sessions.find { it.id == state.sessions.selectedId }?.pendingApproval
+                val active = state.selectedPendingApproval()
                 if (active != null && text.isNotBlank()) {
                     state.copy(inputMode = InputMode.ROUTER, inputBuffer = "") to listOf(
                         Effect.SendWs(

apps/tui/src/main/kotlin/com/correx/apps/tui/state/TuiState.kt

@@ -75,3 +75,6 @@ data class ApprovalInfo(
     val toolName: String?,
     val preview: String?,
 )
+
+fun TuiState.selectedPendingApproval(): ApprovalInfo? =
+    sessions.sessions.find { it.id == sessions.selectedId }?.pendingApproval