[woahwhattheheck]

Closes #19

Adds a typed transaction-receipt surface for compliance updates, minting, transfers, and investor operations, plus a shared network-aware Stellar explorer URL builder.

Key points:

• validates 64-hex transaction hashes and exposes status, amount, timestamp, and failure-code fields;
• treats only null/undefined as an absent transaction hash; an explicitly supplied empty string is validated and rejected as INVALID_TRANSACTION_HASH, including pending/failed/unknown receipts;
• applies the same explicit-empty-hash rule through the backwards-compatible admin receipt path, so public and admin confirmation surfaces do not drift;
• maps Public, Testnet, Futurenet, and plain HTTPS custom explorer bases, rejecting custom bases with credentials, query parameters, or fragments before appending the transaction hash;
• preserves the existing admin API by delegating it through the shared receipt core while retaining AdminReceiptError behavior;
• exports the public receipt types/builders from the SDK entrypoint;
• includes focused tests for Testnet URL construction, pending/no-hash behavior, malformed/explicit-empty hash rejection, admin compatibility, and custom-explorer rejection boundaries;
• documents receipt construction and explorer usage.

Validation boundary:

• Current carrier head: b6f4bc25e1e9ff1293215dce353d153f7eecfd36.
• Earlier branch revisions had focused strict-TypeScript/runtime validation for explorer construction, pending/no-hash handling, invalid-hash rejection, and admin compatibility.
• The current exact head has zero registered commit-status contexts, so no current-head CI/full-suite green claim is made.

Compensation request

Claimant and payee: @woahwhattheheck. This delivered contribution is claimed through the existing /claim #19 registration (issuecomment-6022343109) and issue #19's GrantFox OSS / Maybe Rewarded / Official Campaign FWC26 route. I am requesting the applicable reward. Please confirm assignment, acceptance, the payable amount, payout method, and timing. The compensation claim remains active while those decisions are pending.