feat(phase2): close-empty-ATA flow — build/decode/preview/sign/confirm/receipt

- @pyre/solana: buildCloseEmptyAccountsTx (UNSIGNED v0 tx; re-validates each
  account on-chain — owner==wallet, balance==0, correct program, not
  frozen/delegated, Token-2022 EMPTY_CLOSE_ONLY via §7.1; rejects whole build on
  any ineligible account), simulateTransaction, decodeTransaction. Rent
  destination + close authority + fee payer all pinned to the wallet.
- @pyre/api: POST /api/build/close-empty (server re-validates, 400 on ineligible)
  and POST /api/receipt (on-chain verified: meta.err==null, signer==wallet, rent
  from balance delta; lists only closes whose destination==wallet).
- @pyre/web: select empty accounts → build → CLIENT-SIDE decode+match (7 checks:
  feePayer/all-closeAccount/dest==wallet/closed-set==selected==preview) gates
  signing → sign in wallet → send → confirm → on-chain receipt w/ explorer link.

Built by 3 agents, reviewed by 2 audits (security: SOUND — no critical/high;
integration: SHIP). Applied audit fixes: receipt destination check, doc/lint
cleanup. typecheck 8/8, core 85, solana 19, web build green. Live-verified: the
API refuses to build a close tx for a non-empty account (400). buildBurnTx
remains a Phase-3 stub.

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

CLAUDE.md

@@ -62,9 +62,9 @@ add application/business logic unless explicitly asked.
 supported conservatively with account+mint **extension gating**: confidential
 transfer / withheld transfer fees / frozen / unknown extensions are skipped;
 transfer-hook & permanent-delegate mints are cleanable but flagged. See
-[`docs/PYRE_MVP_DESIGN.md`](docs/PYRE_MVP_DESIGN.md) §7.1. (Note: the classifier
-code currently still skips all Token-2022 as a safe subset until the
-extension-aware implementation lands.)
+[`docs/PYRE_MVP_DESIGN.md`](docs/PYRE_MVP_DESIGN.md) §7.1. Implemented in
+`@pyre/core` (`extensions.ts` + `classify.ts`) and `@pyre/solana` (account+mint
+extension reads); unverifiable mints → UNSUPPORTED.
 
 v0.1 ships: wallet connect → scan token accounts (classic SPL + Token-2022) →
 classify → close eligible empty ATAs (optionally burn obvious junk) → return rent