fix: hide unauthorized edit and delete buttons on org bounties page (#238)

[Ishant5436]

Implementation of synchronized UI and server-side guards to prevent unauthorized bounty management actions.

This PR establishes a defense-in-depth pattern for the organization bounties interface, addressing the vulnerability where administrative actions were exposed to unauthorized actors.

Architectural details:

• Lifecycle Synchronization: Implemented role-based conditional rendering in the LiveView layer, ensuring that management controls are omitted from the DOM for non-privileged users.
• Server-Side Enforcement: Validated that the backend handle_event calls for deletion and modification are strictly gated by the authenticated user's role context.
• Integrity Verification: Added a dedicated integration test suite (test/algora_web/live/org_bounties_live_test.exs) that confirms the unreachability of administrative events for non-admin sessions.

Settlement Information:

• Solana: 2WktXRjaQ4GKhj6FJhUSndTBLVjxrk43TQwyywehneDA
• Institutional ID: ishant.p@somaiya.edu

[CLAassistant]

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