docs(lnurlcash): update the minting contract and test harness description

src/lnurlcash/AGENTS.md

@@ -6,14 +6,11 @@ lnurlcash-kit directly.
 
 ## FUND-CRITICAL INVARIANTS (non-negotiable)
 
-- Rotate on every receive, and immediately after claiming a fresh mint
-  from an UNNAMED mint (one that keys the note by the payment preimage).
-  A NAMED mint (LUD-25 `comment`/`mintToHash`, required by lnurl-mint
-  ≥ 0.4) credits the note to a wallet-chosen secret whose hash bound the
-  quote; that secret never rode an invoice, so the claim needs no rotate.
-  The claim poll itself is the placement proof: a mint that took the hash
-  but credited the preimage is caught there and rescued through the
-  quote's verify URL when one is served.
+- Rotate every externally received bearer. Minted notes are different:
+  current LUD-25 requires `commentAllowed >= 64`, so the wallet durably
+  stages its chosen secret before requesting the invoice and claims at
+  that secret without rotating. `mintToHash` is only an additive receipt
+  extension, never a capability fallback.
 - A note's declared amount is a claim; the service's `maxWithdrawable` is
   authoritative.
 - A melt's "OK" only means the payment is in flight — the verify URL (or
@@ -68,7 +65,6 @@ test-utils.ts    # mock mint harness used by *.test.ts
 ## TESTS
 
 `npx vitest run` — node environment, `*.test.ts` next to the modules.
-Adversarial mock mint from lnurlcash-conformance via `ops.testHarness.ts`
-(`conformance-mockmint.d.ts` augments its stale published declarations
-with the comment-naming flags). The mock's `commentAllowed` option models
-the named-mint generation; default options model the old one.
+The adversarial mock mint from lnurlcash-conformance is wrapped by
+`ops.testHarness.ts`; its default contract is mandatory comment-bound
+minting.