feat(sproutclaw): modularize webui, extensions, and agent config layout

Restructure local extensions into per-feature directories, split WebUI
into backend modules with slash commands and systemd support, and track
prompts/skills under .pi/agent for portable Gitea deployment.

Co-authored-by: Cursor <cursoragent@cursor.com>

.pi/agent/extensions/webui/backend/routes/models.ts

@@ -0,0 +1,43 @@
+import type { IncomingMessage, ServerResponse } from "node:http";
+import type { WebUiContext } from "../types/context.ts";
+import { json, readBody } from "../http/request.ts";
+
+export function handleModelsRoute(
+	req: IncomingMessage,
+	res: ServerResponse,
+	ctx: WebUiContext,
+	pathname: string,
+): boolean {
+	const { sendCmd } = ctx.rpc;
+
+	if (req.method === "GET" && pathname === "/api/models") {
+		void sendCmd({ type: "get_available_models" })
+			.then((r: any) => (r.success ? json(res, r.data) : json(res, { error: r.error }, 500)))
+			.catch((err) => json(res, { error: err.message }, 500));
+		return true;
+	}
+
+	if (req.method === "POST" && pathname === "/api/model") {
+		void readBody(req)
+			.then(({ provider, modelId }) =>
+				sendCmd({ type: "set_model", provider, modelId }).then((r: any) =>
+					r.success ? json(res, { model: r.data }) : json(res, { error: r.error }, 500),
+				),
+			)
+			.catch((err) => json(res, { error: err.message }, 500));
+		return true;
+	}
+
+	if (req.method === "POST" && pathname === "/api/thinking") {
+		void readBody(req)
+			.then(({ level }) =>
+				sendCmd({ type: "set_thinking_level", level }).then((r: any) =>
+					r.success ? json(res, { ok: true }) : json(res, { error: r.error }, 500),
+				),
+			)
+			.catch((err) => json(res, { error: err.message }, 500));
+		return true;
+	}
+
+	return false;
+}