feat(agent): support Responses steering and project-aware tools

Use the dedicated TJWATER_AGENT_URL and Responses stream protocol. Keep running
turns active while users steer or queue follow-ups and edit pending delivery.
Refresh the model catalog before generation and preserve approval mode selection.

Integrate scoped investigation messaging/presentation, geographic place selection,
current Agent composer styles and supporting workbench contracts.

Validation: 77 focused Vitest checks, 21 browser cases, lint, typecheck and
production build. Preserve direct Server/Agent routing and project authentication.

src/features/agent/api/swr.ts

@@ -1,7 +1,8 @@
 import type {
   AgentApiClient,
   AgentChatSessionSummary,
-  AgentModelOption
+  AgentModelOption,
+  AgentModelsResponse
 } from "./client";
 import { parseUiRegistry, type UIRegistry } from "../ui-envelope";
 import { parseFrontendActionRegistry, type FrontendActionRegistry } from "../frontend-action";
@@ -16,6 +17,12 @@ export type AgentBootstrapData = {
   defaultModel: string;
 };
 
+export function resolveAgentModelSelection(catalog: AgentModelsResponse, current = ""): string {
+  if (catalog.models.some((model) => model.id === current)) return current;
+  if (catalog.models.some((model) => model.id === catalog.defaultModel)) return catalog.defaultModel;
+  return catalog.models[0]?.id ?? "";
+}
+
 export async function fetchAgentBootstrap(client: AgentApiClient): Promise<AgentBootstrapData> {
   const [rawRegistry, rawFrontendActionRegistry, modelsResponse] = await Promise.all([
     client.getUiRegistry(),