[Contracts] Implement get_plan Query Interface

[ONEONUORA]

Description

Create a read-only query entrypoint get_plan:

• Reads plan data structure from storage.
• Returns plan details, including remaining time, allocations, and active state.

Acceptance Criteria

• Does not modify ledger state.
• Returns clear errors if plan is not found.
• Bumps temporary TTL if queried.

[ekwe7]

I would love to work on this issue. I have experience building production ready applications and collaborating through GitHub workflows. I'll carefully analyze the current implementation, propose a reliable solution, and submit a well-tested PR. My focus is on clean code, maintainability, and timely delivery

[ejioforJs]

@ejioforJs has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello,i would like to work on this issue.

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

[chuks68]

@chuks68 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue because i am confident i can resolve the issue, having worked on and resolved similar issues. my eta is 4 hours

ℹ️ Repo Maintainers: To accept this application, review their application or assign @chuks68 to this issue.

[drips-wave]

Congratulations, @chuks68! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @chuks68: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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