make session TTL configurable via MCP_SESSION_TTL_MS

[prachishah-harness]

Summary

• Replaces the hardcoded SESSION_TTL_MS = 30 * 60_000 constant in src/index.ts with a MCP_SESSION_TTL_MS config field (Zod-validated, z.coerce.number().min(1))
• Default value is 5 minutes (300000 ms)
• Documented in .env.example alongside the other timeout/retry knobs
• The value is read from config.MCP_SESSION_TTL_MS inside startHttp, so it correctly picks up the parsed+validated config rather than a module-level constant

Test plan

• Start the HTTP server without MCP_SESSION_TTL_MS set — sessions should expire after 5 minutes (new default)
• Set MCP_SESSION_TTL_MS=60000 and confirm sessions are reaped after 1 minute of inactivity
• Set MCP_SESSION_TTL_MS=0 and confirm config validation rejects it (min(1))

Made with Cursor

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