Baseline
Required for the baseline, limited-conn, noisy, and mixed profiles.
GET/POST /baseline11?a=N&b=N
Parse query parameters a and b, compute their sum, and return it as plain text.
For POST requests, the body contains an additional integer to add. The server must accept both Content-Length and chunked Transfer-Encoding bodies.
GET /baseline11?a=13&b=42 → "55"
POST /baseline11?a=13&b=42 (body: "20") → "75"Response must have Content-Type: text/plain.