User Story: Station Bot RSI HTTP tuning controls

[GitAddRemote]

User Story

As a Station super admin, I need to manage RSI HTTP tuning controls so that I can tune timeouts, retries, concurrency, and pacing for RSI integration requests.

Definition of Done

• Station exposes RSI_HTTP_TIMEOUT_MS, RSI_HTTP_MAX_RETRIES, RSI_HTTP_RETRY_BASE_MS, RSI_HTTP_MAX_CONCURRENCY, and RSI_HTTP_MIN_INTERVAL_MS
• Validation and save/reload flows are covered by tests
• Guild owners/admins cannot access these controls
• pnpm typecheck passes

Acceptance Criteria

• A station_super_admin can update RSI HTTP tuning settings from Station
• Invalid values are rejected with field-level validation
• Guild-scoped admins cannot access these controls

Technical Elaboration

This ticket covers RSI transport/performance tuning only. It is separate from RSI URL/pattern settings.

Design Elaboration

This UI should feel like an integration tuning panel. Units and operational consequences should be explicit so changes are made deliberately.

---

Parent Epic: #231
Depends on: #232, #233, #242