Fix master compilation after bad story 86 squash merge revert

The revert of story 86's merge left broken code from stories 131/135
that depended on it. Removed dead inline event dispatch (referencing
undefined event_type, pty_writer, PermissionReqMsg), added activity_tx
to process_json_event, and removed unused permission_tx parameter from
chat_stream/chat (permissions go through MCP, not PTY).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/llm/chat.rs

@@ -187,11 +187,6 @@ pub async fn chat<F, U, A>(
     mut on_update: F,
     mut on_token: U,
     mut on_activity: A,
-    permission_tx: Option<
-        tokio::sync::mpsc::UnboundedSender<
-            crate::llm::providers::claude_code::PermissionReqMsg,
-        >,
-    >,
 ) -> Result<ChatResult, String>
 where
     F: FnMut(&[Message]) + Send,
@@ -249,7 +244,6 @@ where
                 &mut cancel_rx,
                 |token| on_token(token),
                 |tool_name| on_activity(tool_name),
-                permission_tx,
             )
             .await
             .map_err(|e| format!("Claude Code Error: {e}"))?;