fix: gate initialPrompt on feed readiness, not just auth resolution

Move prompt send back into useSessionFeed where it waits for the event
stream. Add canSendPrompt accessor so session-controller gates on auth.
Fixes premature send/drop race identified in counsel review. Remove
authGatePending from public SessionController interface.

Author: cevr

apps/tui/src/hooks/use-session-feed.ts

@@ -259,6 +259,7 @@ export function useSessionFeed(
   cast: <A, E>(effect: Effect.Effect<A, E, never>) => void,
   callbacks: SessionFeedCallbacks,
   initialPrompt?: string,
+  canSendPrompt?: () => boolean,
 ): SessionFeed {
   const [store, setStore] = createStore<{ messages: Message[]; events: SessionEvent[] }>({
     messages: [],
@@ -380,8 +381,16 @@ export function useSessionFeed(
                   Effect.forkScoped,
                 )
 
-                // Send the prompt only after the event stream is established.
+                // Send the prompt only after the event stream is established
+                // and the caller signals readiness (e.g. auth gate resolved).
                 if (initialPrompt !== undefined && initialPrompt !== "" && !sentPrompts.has(key)) {
+                  // Wait for canSendPrompt if provided (polls via short sleep)
+                  if (canSendPrompt !== undefined) {
+                    while (!canSendPrompt()) {
+                      yield* Effect.sleep("50 millis")
+                      if (currentKey !== key) return yield* Fiber.join(eventsFiber)
+                    }
+                  }
                   sentPrompts.add(key)
                   client.log.info("feed.sendInitialPrompt", {
                     sessionId: session,

apps/tui/src/routes/session-controller.ts

@@ -89,7 +89,6 @@ export interface SessionController {
   onSessionTreeSelect: (sessionId: SessionId) => void
   onForkSelect: (messageId: MessageId) => void
   onPromptSearchEvent: (event: Extract<SessionUiEvent, { _tag: "PromptSearch" }>["event"]) => void
-  authGatePending: () => boolean
 }
 
 const SPINNER_FRAMES = ["·", "•", "*", "⁑", "⁂"]
@@ -273,20 +272,11 @@ export function createSessionController(props: {
         router.navigateToSession(sessionId, branchId)
       },
     },
-    // Never pass initialPrompt to feed — we control prompt sending through the auth gate.
-    undefined,
+    props.initialPrompt,
+    // Gate prompt send on auth resolution — feed waits for stream + this signal
+    () => !authGatePending(),
   )
 
-  // Send initial prompt once auth resolves and feed is ready
-  if (props.initialPrompt !== undefined && props.initialPrompt !== "") {
-    let promptSent = false
-    createEffect(() => {
-      if (promptSent || authGatePending()) return
-      promptSent = true
-      client.sendMessage(props.initialPrompt ?? "")
-    })
-  }
-
   const items = createMemo<SessionItem[]>(() => feed.items())
   const promptSearch = createPromptSearchController({
     state: () => getPromptSearchState(uiState()),
@@ -627,7 +617,6 @@ export function createSessionController(props: {
     onSessionTreeSelect,
     onForkSelect,
     onPromptSearchEvent: (event) => promptSearch.onEvent(event),
-    authGatePending,
   }
 }