Fix code scanning alerts: rate limiting, SSRF, CORS, JSON injection, X-Frame-Options

[Copilot]

Addresses five active code scanning alerts across multiple sample apps. Alert #22 (CSRF on PermissionsController) is a false positive — Startup.cs already registers AutoValidateAntiforgeryTokenAttribute as a global MVC filter.

Changes

• Bump @adobe/css-tools from 4.0.1 to 4.3.2 in /Samples/spa-azurefunction/packages/client-app #12 — Missing rate limiting (AI/mcp-server/src/server.ts)
  Added express-rate-limit (100 req / 15 min window) on POST /messages.

• Bump word-wrap from 1.2.3 to 1.2.5 in /Samples/spa-azurefunction/packages/client-app #13 — SSRF (Custom Apps/webhook/src/server.js)
  Validates notification.resource against ^[A-Za-z0-9_\-/]+$ before interpolating into the Graph API URL. Dots excluded to eliminate traversal risk.

• Error when debugging asp.net web service #14 — CORS origin reflection (AI/ocr/server/index.ts)
  Replaced req.header('origin') echo with an explicit allowlist. Configurable via ALLOWED_ORIGINS env var.

  // Before — reflects any origin
  res.header('Access-Control-Allow-Origin', req.header('origin'));
  
  // After — allowlist only
  const allowed = getAllowedOrigins();
  if (origin && allowed.includes(origin)) {
    res.header('Access-Control-Allow-Origin', origin);
  }

• Bump jose from 4.11.1 to 4.15.5 in /Samples/spa-azurefunction #24 — JSON injection (boilerplate-aspnet-webservice/Services/MSGraphService.cs)
  Replaced manual string interpolation for the roles payload with JsonConvert.SerializeObject, so role is properly escaped.

• Bump jose from 4.11.1 to 4.15.5 in /Samples/spa-azurefunction/packages/azure-functions #25 — Clickjacking (boilerplate-react-azurefunction/packages/azure-functions/web.config)
  Added X-Frame-Options: DENY via <httpProtocol><customHeaders>.

False Positive

• Fixed preview for PNG files and download button #22 — CSRF on PermissionsController: AutoValidateAntiforgeryTokenAttribute is registered as a global filter in Startup.cs, covering all state-mutating actions. CodeQL does not trace through global filter registration.