SLN Phase 1: Internal Credit Ledger System

## Summary

Implement the SLN credit economy as an internal ledger on Supabase. This is Phase 1 of the SAL Protocol — a launch-ready credit system with zero blockchain dependency. Users see "credits" or "SLN balance" while the underlying mechanics are forward-compatible with on-chain settlement in later phases.

## Key Details

**Exchange Rate:** Fixed at 1000 SLN = €10 (1 SLN = €0.01)

**Onboarding:** New users receive +100 SLN (~€1.00) on email confirmation, plus 5 invite slots.

**Invite System:**

- Sending an invite costs 20 SLN

- When invitee publishes a site: inviter gets +100 SLN (5x return)

- When invitee upgrades to Basic: inviter gets +500 SLN bonus + 200 SLN commission

- When invitee upgrades to Premium/Pro: inviter gets +1000 SLN bonus + 400-800 SLN commission

- Maximum return per invite: 1,600 SLN on 20 SLN investment (80x)

**Commission on Upgrades:** 20% of the subscription's first payment, converted to SLN at fixed rate. Recurring commissions deferred to Phase 2.

**Spending SLN (at launch):**

- Send invite: 20 SLN

- Apply as subscription discount: 1:1 at €0.01/SLN

- Upgrade to Basic Monthly: 1000 SLN

- Cash out: Min 1000 SLN (€10), PayPal or bank transfer, manual review, monthly

**Credit Expiry:** 24 months of account inactivity (no login)

## Database Changes

- Extend `user_profiles` with `sln_balance`, `invite_slots_total`, `invite_slots_used`

- New table: `sln_transactions` (full double-entry ledger with type, amount, balance_after)

- New table: `sln_cashout_requests` (manual payout queue)

- Extend `invite_requests` with inviter tracking

- Atomic `credit_sln` RPC function for all balance mutations

- Daily reconciliation query to verify balance integrity

## New API Routes

| Route | Method | Purpose |

|---|---|---|

| `/api/sln/balance` | GET | Current SLN balance and slot count |

| `/api/sln/transactions` | GET | Paginated transaction history |

| `/api/sln/cashout` | POST | Submit cash-out request |

| `/api/sln/apply-discount` | POST | Calculate SLN discount for checkout |

| `/api/admin/sln/cashouts` | GET | Pending cash-out requests (admin) |

| `/api/admin/sln/cashouts/[id]` | PATCH | Approve/reject cash-out |

| `/api/admin/sln/adjust` | POST | Manual balance adjustment |

## Integration Points

1. **Signup flow** — +100 SLN on email confirmation

2. **Invite flow** — SLN debit on send, reward on invitee site publish

3. **Stripe webhook** — Commission on referred user's first subscription payment

4. **Checkout flow** — SLN discount support with atomic debit on payment confirmation

5. **Settings page** — Replace invite placeholder with full balance/transaction/cashout UI

## Phase 2 Migration Path

Phase 1 Supabase ledger maps 1:1 to Phase 2 on-chain (BSV-20 SLN tokens). User balances minted as tokens, transaction history archived, UI stays the same. Only visible change is a wallet connection step.

*Full spec: `new-salon-app/docs/ongoing/SLN-PHASE-1-INTERNAL-LEDGER.md`*