Adopt session.redirect (issue #710) (#714)

* Add session.redirect affordance (issue #710)

Route send through session.redirect while a turn is streaming and the prompt
is plain text (no attachments, not a /command); otherwise prompt.submit.
Adds WsMethods.SESSION_REDIRECT + HermesWsClient.sendRedirect. No separate
button — the composer already sends mid-turn, so send just does the redirect.

* fix(chat): capture typing state before sendMessage for redirect

Capture wasStreaming state before updating uiState.isAgentTyping so normal sends call prompt.submit.

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatViewModel.kt

@@ -765,6 +765,8 @@ class ChatViewModel(
         val attachments = _uiState.value.pendingAttachments.toList()
         clearAttachments()
 
+        val wasStreaming = _uiState.value.isAgentTyping
+
         val userMessage =
             ChatMessage(
                 role = MessageRole.USER,
@@ -857,11 +859,24 @@ class ChatViewModel(
                         if (text.isNotBlank()) "\n\n$text" else ""
                 }
 
-            wsClient.sendMessage(
-                agentSessionId,
-                fullText,
-                onSent = { id -> trackRequest(id, WsMethods.PROMPT_SUBMIT) },
-            )
+            // While a turn is actively streaming and this is a plain text prompt
+            // (no attachments — session.redirect carries text only), steer the
+            // in-flight turn via session.redirect instead of queueing a fresh
+            // prompt.submit. The backend rewrites the live turn when it can, or
+            // queues the correction as the next turn otherwise (issue #710).
+            if (wasStreaming && attachments.isEmpty()) {
+                wsClient.sendRedirect(
+                    agentSessionId,
+                    fullText,
+                    onSent = { id -> trackRequest(id, WsMethods.SESSION_REDIRECT) },
+                )
+            } else {
+                wsClient.sendMessage(
+                    agentSessionId,
+                    fullText,
+                    onSent = { id -> trackRequest(id, WsMethods.PROMPT_SUBMIT) },
+                )
+            }
         }
     }