feat(lnbits): new @bitSpire/lnbits package — LNbits client over the nostr-native-transport

New TypeScript workspace package targeting aiolabs/lnbits's
nostr-native-transport (kind-21000 NIP-44 v2 RPC). Designed as a
drop-in peer of @bitSpire/lightning's LightningPubClient so the
machine app can swap backends with minimal churn (3b).

  packages/lnbits/
    package.json            workspace + nostr-tools deps
    tsconfig.json           extends root config
    src/types.ts            wire envelope, Payment, WalletInfo,
                            SubscribePayments filter / ack / push,
                            WithdrawLink, PayLink, callback types
    src/client.ts           LnbitsClient with:
                              getWallet / getBalance / listWallets
                              createInvoice / payInvoice
                              getPayment / decodePayment
                              subscribePayments / unsubscribe
                              watchInvoice (resolve-on-paid)
                              watchWallet (cancel-fn)
                              createWithdrawLink / getWithdrawLink
                              listWithdrawLinks / updateWithdrawLink
                              deleteWithdrawLink
                              getWithdrawLinkUniqueHashes
    src/index.ts            public exports

Key differences vs LightningPubClient:
  - Auth: signing pubkey IS the credential (no authIdentifier/appId
    in the request envelope).
  - Subscriptions: one `subscribe_payments` RPC handles all three
    cases (payment_hash, wallet_id, tag+link_id). Server emits an
    ack first, then push events sharing subscription_id. unsubscribe
    teardown emits a closed-push immediately followed by ACK.
  - Sharding: outbound responses ≤40K plaintext arrive as a single
    event. Larger responses come back as multiple kind-21000 events
    sharing a `shardsId`; client reassembly is TODO (lazy: ATM RPCs
    rarely return that much data).
  - CLINK/ndebit/noffer is NOT covered — LNbits has no CLINK. For
    the ATM that means cash-in uses lnurlw + subscribe_payments
    instead of ndebit (wired in 3b).

Reuses @bitSpire/nostr-client's encryptContentV2 / decryptContentV2
(NIP-44 v2 via nostr-tools/nip44). No new crypto code.

tsconfig.json path mapping added so `@bitSpire/lnbits` imports
resolve to ./packages/lnbits/src across the monorepo.

Verified: pnpm typecheck clean (13/13 turbo tasks).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tsconfig.json

@@ -26,6 +26,7 @@
       "@bitSpire/clink": ["./packages/clink/src"],
       "@bitSpire/state-machine": ["./packages/state-machine/src"],
       "@bitSpire/lightning": ["./packages/lightning/src"],
+      "@bitSpire/lnbits": ["./packages/lnbits/src"],
       "@bitSpire/cashu": ["./packages/cashu/src"],
       "@bitSpire/ui-shared": ["./packages/ui-shared/src"],
       "@bitSpire/hal": ["./packages/hal"]