feat(fee+burn+essence): 5% transparent fee, burn→close, Essence ledger + dashboard

Monetization (design Rev 4, §3.1) — transparent in-tx fee, non-custodial:
- @pyre/core: computeFeeBreakdown (single source of truth, BigInt) + FeeBreakdown
  threaded through close/burn previews; fee tests.
- @pyre/config: PYRE_TREASURY_WALLET / PYRE_FEE_BPS (500) / swap fee / max contribution.
- @pyre/solana: close-empty + burn→close now append ONE System transfer of exactly
  the disclosed fee to the treasury; rent/authority/feePayer pinned to wallet.
  buildBurnTx re-validates EVERY account on-chain and value-gates via the classifier
  (classic SPL + Token-2022) — never burns protected/valuable/NFT/unsupported;
  ignores client amount (burns real balance); whole-build rejection.
- @pyre/api: close-empty/burn endpoints carry the fee + bounded optional contribution;
  /api/receipt persists (cleanup_receipts) and records the on-chain treasury fee as
  Essence; GET /api/essence; startup migrate(). Best-effort DB (never fails receipts).
- @pyre/db: Postgres Essence ledger (rounds, cleanup_receipts, essence_contributions),
  idempotent migrations, parameterized + u64-safe.
- @pyre/web: fee preview ("reclaim · feeds the PYRE · you net" + treasury) + optional
  "feed more" slider; burn flow w/ destructive confirm; decode+match verifies the fee
  transfer (treasury + exact lamports) before signing; public "🔥 fed the PYRE" panel.

Built by agents (2 waves) + 2 audits. Security audit found a HIGH — buildBurnTx
didn't value-gate CLASSIC spl tokens (a direct API caller could burn USDC/an NFT);
FIXED (classify classic accounts too) + 2 regression tests. Integration: SHIP.
typecheck 8/8, core 91, solana 30, web build green. Live: burn preview on the dust
token shows 5% → treasury; non-empty/non-owned/valuable rejected. Nightly DB backup
cron enabled.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/core/src/fee.test.ts

@@ -0,0 +1,87 @@
+import { describe, it, expect } from "vitest";
+import { computeFeeBreakdown } from "./fee.js";
+
+const TREASURY = "6dNVUMrJ8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8C8";
+
+describe("computeFeeBreakdown", () => {
+  it("takes a 5% base fee of the gross (500 bps of 1_000_000 = 50_000; net 950_000)", () => {
+    const fee = computeFeeBreakdown({
+      grossLamports: 1_000_000n,
+      feeBps: 500,
+      treasury: TREASURY,
+    });
+    expect(fee.grossLamports).toBe("1000000");
+    expect(fee.feeBps).toBe(500);
+    expect(fee.feeLamports).toBe("50000");
+    expect(fee.totalToTreasuryLamports).toBe("50000");
+    expect(fee.netToUserLamports).toBe("950000");
+    expect(fee.treasury).toBe(TREASURY);
+    // No contribution requested → fields omitted.
+    expect(fee.contributionBps).toBeUndefined();
+    expect(fee.contributionLamports).toBeUndefined();
+  });
+
+  it("adds an optional contribution on top of the base fee", () => {
+    const fee = computeFeeBreakdown({
+      grossLamports: 1_000_000n,
+      feeBps: 500, // 50_000
+      contributionBps: 200, // 20_000
+      treasury: TREASURY,
+    });
+    expect(fee.feeLamports).toBe("50000");
+    expect(fee.contributionBps).toBe(200);
+    expect(fee.contributionLamports).toBe("20000");
+    expect(fee.totalToTreasuryLamports).toBe("70000");
+    expect(fee.netToUserLamports).toBe("930000");
+  });
+
+  it("caps the contribution at maxContributionBps", () => {
+    const fee = computeFeeBreakdown({
+      grossLamports: 1_000_000n,
+      feeBps: 500,
+      contributionBps: 5_000, // requested 50%
+      maxContributionBps: 300, // capped to 3% = 30_000
+      treasury: TREASURY,
+    });
+    expect(fee.contributionBps).toBe(300);
+    expect(fee.contributionLamports).toBe("30000");
+    expect(fee.totalToTreasuryLamports).toBe("80000"); // 50_000 + 30_000
+    expect(fee.netToUserLamports).toBe("920000");
+  });
+
+  it("never lets the total exceed gross (net is never negative)", () => {
+    const fee = computeFeeBreakdown({
+      grossLamports: 1_000_000n,
+      feeBps: 9_000, // 90%
+      contributionBps: 9_000, // +90% → would be 180% of gross
+      maxContributionBps: 10_000,
+      treasury: TREASURY,
+    });
+    expect(BigInt(fee.totalToTreasuryLamports)).toBeLessThanOrEqual(1_000_000n);
+    expect(fee.totalToTreasuryLamports).toBe("1000000");
+    expect(fee.netToUserLamports).toBe("0");
+    expect(BigInt(fee.netToUserLamports)).toBeGreaterThanOrEqual(0n);
+  });
+
+  it("0 bps → 0 fee, full amount to the user", () => {
+    const fee = computeFeeBreakdown({
+      grossLamports: 1_000_000n,
+      feeBps: 0,
+      treasury: TREASURY,
+    });
+    expect(fee.feeLamports).toBe("0");
+    expect(fee.totalToTreasuryLamports).toBe("0");
+    expect(fee.netToUserLamports).toBe("1000000");
+  });
+
+  it("accepts a string gross and stays exact for large u64 values", () => {
+    const fee = computeFeeBreakdown({
+      grossLamports: "18446744073709551615", // u64 max
+      feeBps: 500,
+      treasury: TREASURY,
+    });
+    expect(fee.grossLamports).toBe("18446744073709551615");
+    // 5% of u64 max, BigInt-exact.
+    expect(fee.feeLamports).toBe("922337203685477580");
+  });
+});