Add stream access permission model separating read and admin roles

[Chuks-coderr]

Overview

All admin instructions share a single admin address. As the protocol grows, different operators may need read-only analytics access, fee-parameter changes, or emergency pause authority without sharing a single admin key.

Problem

A monolithic admin role creates a single point of failure and makes fine-grained operational security impossible. Compromise of the admin key would expose all privileged operations.

Proposed Solution

• Introduce a role registry: Admin, FeeManager, PauseOperator, ReadAnalytics
• Each role maps to one or more authorized addresses stored in persistent storage
• Restrict instructions to the appropriate role (e.g. only PauseOperator can call pause)
• Admin role can assign and revoke all other roles

Acceptance Criteria

• Role registry stores multiple addresses per role
• Each privileged instruction checks the correct role and returns StreamError::Unauthorized on mismatch
• Admin can add/remove addresses from each role
• Unit tests cover: correct role accepted, wrong role rejected, role reassignment
• Role assignments emit events for auditability

[githoboman]

@githoboman has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

hello would love to work on this project

ℹ️ Repo Maintainers: To accept this application, review their application or assign @githoboman to this issue.

[drips-wave]

Congratulations, @Abigail6168! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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