Add explicit split payout approval

[FJAC-web]

Summary

• Add an optional splitPayouts approval payload so maintainers can explicitly distribute a locked bounty across multiple GitHub contributors.
• Validate split recipients by unique GitHub username and exact cent-level total before sending any payout.
• Resolve each recipient through their PR wallet tag, registered email fallback, or unclaimed payout flow, then persist payout/activity rows per recipient.
• Add a maintainer UI for split rows prefilled from competing PR activity, while keeping the existing single-winner approval path unchanged.
• Document the multi-contributor approval contract in public/LLM.md for agent-readable usage.

Validation

• tsc --noEmit
• focused ESLint on touched files
• git diff --check

Fixes #12

[vercel]

@FJAC-web is attempting to deploy a commit to the skndash96's projects Team on Vercel.

A member of the Team first needs to authorize it.

[bountic-bot]

⚡️ Bounty Competition Started

@FJAC-web has submitted a PR that references an issue with a bounty. Learn more about this bounty: https://bountic.vercel.app/b/skndash96/bountic/issues/12

When this PR is merged, the bounty will be locked and ready for payout approval.

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Bountic: Autonomous USDC bounties for open source

[FJAC-web]

Small note on the visible check: the Vercel failure is the standard fork authorization gate (A member of the Team first needs to authorize it), not a code/test failure from this branch.

Local validation completed before opening the PR:

• tsc --noEmit
• focused ESLint on the touched files
• git diff --check

[FJAC-web]

Additional local validation:

• next build passes with the required env vars present (dummy local values used only for validation).
• A plain next build without env compiles and typechecks, then fails during prerender because NEXT_PUBLIC_APP_URL, Supabase, and service keys are required by the app environment schema.
• Full-repo eslint still reports pre-existing issues outside this branch (app/mock-checkout/[checkoutId]/page.tsx, app/page.tsx, plus warnings). Focused ESLint on this branch's touched files passes.