feat: Advanced features (RBAC, Tracing, Multi-tenant, Wallets)

[Queenode]

Advanced Contract Features, Observability, and Wallet UX Improvements

Summary

This PR introduces massive architectural improvements across the Trivela stack to improve security, observability, and user experience.

Changes

1. Role-based access control (RBAC) beyond single admin

• Refactored Soroban contracts (rewards and campaign) to replace the single all-powerful admin with a granular RBAC module.
• Introduced specific roles: admin, operator, pauser, treasurer.
• Each privileged function now strictly checks for the appropriate role, reducing blast radius and enabling safe delegation to campaign operators.

2. Multi-campaign / multi-tenant isolation model

• Updated smart contracts to support multiple concurrent campaigns securely.
• Namespaced storage and reserves per campaign ID.
• Added cross-tenant safety guards to prevent one campaign from accessing or leaking data to another campaign's state or analytics.

3. Distributed tracing across backend -> RPC -> contract calls

• Extended the backend tracing module to propagate trace context entirely through the backend, Soroban RPC calls, and background jobs.
• Instrumented RPC connection pools and the outbox service with OpenTelemetry spans.
• Traces can now be exported to an OTLP-compatible backend, providing end-to-end visibility of latency and errors.

4. Wallet integration: Freighter + WalletConnect + hardware wallet support

• Built a unified wallet provider interface in the React frontend (WalletManager.js).
• Implemented full support for Freighter and WalletConnect (v2).
• Added network mismatch detection to alert users when they are on the wrong network (e.g. mainnet vs testnet).
• Handled seamless account switching events and state restoration.

Verification

• Added comprehensive unit and fuzz tests for RBAC role grants, revocations, and unauthorized access.
• Confirmed cross-tenant isolation with integration tests ensuring campaigns are strictly isolated.
• Verified trace propagation across API -> RPC -> Background Job locally with Jaeger.
• Manually tested Freighter and WalletConnect on both desktop and mobile, ensuring network mismatches correctly guide the user.

Closes

Closes #894
Closes #893
Closes #875
Closes #863

[Queenode]

Closed in favor of #1156