Add distribute funds button for pool creators

[Ugasutun]

Description

Allow pool creators to distribute funds to approved
applicants directly from the pool detail page.

Expected behavior

• Only visible to pool creator
• Button on each approved application
• Confirmation modal before distributing
• Signs and submits distribute transaction via Freighter
• Updates application status after distribution

Tech

• distribute() endpoint from backend
• Freighter signTransaction
• useWallet store to check if creator