feat: add config-owned direct skill submit path

Add fixed direct-submit skill loading from configured staged skills and validate directSubmitSkill early so malformed configs fail before routing.

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

src/agent/mod.rs

@@ -219,6 +219,31 @@ pub fn handle_browser_message_with_context<T: Transport + 'static>(
                             settings.runtime_profile, settings.skills_prompt_mode
                         ),
                     });
+                    if settings
+                        .direct_submit_skill
+                        .as_deref()
+                        .map(str::trim)
+                        .is_some_and(|value| !value.is_empty())
+                    {
+                        let _ = send_mode_log(transport, "direct_skill_primary");
+                        let completion = match crate::compat::direct_skill_runtime::execute_direct_submit_skill(
+                            browser_tool.clone(),
+                            &instruction,
+                            &task_context,
+                            &context.workspace_root,
+                            &settings,
+                        ) {
+                            Ok(summary) => AgentMessage::TaskComplete {
+                                success: true,
+                                summary,
+                            },
+                            Err(err) => AgentMessage::TaskComplete {
+                                success: false,
+                                summary: err.to_string(),
+                            },
+                        };
+                        return transport.send(&completion);
+                    }
                     if crate::compat::orchestration::should_use_primary_orchestration(
                         &instruction,
                         task_context.page_url.as_deref(),