fix(showcase/ms-agent-python): drop trailing slash on subpath HttpAgent URLs

The mcp-apps and voice-demo HttpAgent URLs had a trailing slash
(`${AGENT_URL}/mcp-apps/`, `${AGENT_URL}/voice/`), but the FastAPI
backend in agent_server.py mounts those agents at `/mcp-apps` and
`/voice` exactly. Posting to the trailing-slash URL triggers FastAPI's
default `redirect_slashes` 307, which drops the SSE streaming body and
surfaces in the runtime as
`RUN_ERROR: fetch failed (INCOMPLETE_STREAM)` for every pill click on
the deployed ms-agent-python showcase.

Reproduced live against showcase-ms-agent-python-production. Every
other ms-agent-python HttpAgent URL (`/hitl-in-app`,
`/headless-complete`, `/multimodal`, `/agent-config`, etc.) already
uses no trailing slash and works fine, confirming the trailing slash
is the only delta.

Author: AlemTuzlak

showcase/integrations/ms-agent-python/src/app/api/copilotkit-mcp-apps/[[...slug]]/route.ts

@@ -25,7 +25,12 @@ import { HttpAgent } from "@ag-ui/client";
 
 const AGENT_URL = process.env.AGENT_URL || "http://localhost:8000";
 
-const mcpAppsAgent = new HttpAgent({ url: `${AGENT_URL}/mcp-apps/` });
+// No trailing slash on the URL. FastAPI mounts this agent at `/mcp-apps`
+// exactly (via `add_agent_framework_fastapi_endpoint(path="/mcp-apps")` in
+// agent_server.py); posting to `/mcp-apps/` triggers FastAPI's
+// redirect-to-canonical 307, which kills the streaming SSE response and
+// surfaces as `fetch failed` / `INCOMPLETE_STREAM` in the runtime.
+const mcpAppsAgent = new HttpAgent({ url: `${AGENT_URL}/mcp-apps` });
 
 // headless-complete shares this runtime because its cell also exercises
 // MCP Apps activity rendering (the "Sketch a diagram" pill exercises the

showcase/integrations/ms-agent-python/src/app/api/copilotkit-voice/[[...slug]]/route.ts

@@ -29,7 +29,13 @@ const AGENT_URL = process.env.AGENT_URL || "http://localhost:8000";
 
 // Point at the tool-free /voice endpoint so aimock returns a direct text
 // response instead of a tool call that the agent can't summarize.
-const voiceDemoAgent = new HttpAgent({ url: `${AGENT_URL}/voice/` });
+//
+// No trailing slash on the URL. FastAPI mounts this agent at `/voice`
+// exactly (via `add_agent_framework_fastapi_endpoint(path="/voice")` in
+// agent_server.py); posting to `/voice/` triggers FastAPI's
+// redirect-to-canonical 307, which kills the streaming SSE response and
+// surfaces as `fetch failed` / `INCOMPLETE_STREAM` in the runtime.
+const voiceDemoAgent = new HttpAgent({ url: `${AGENT_URL}/voice` });
 
 /**
  * Transcription service wrapper that reports a clean, typed auth error when