NewClient hardcoded its *http.Client, so a server-side caller making
requests to an attacker-influenced baseURL (a tenant's prime_endpoint)
had no way to attach an SSRF policy — the transport followed redirects
and dialed any resolved IP, reachable being the cloud metadata service.
Add NewClientWithHTTPClient + NewDragonchainSDKWithHTTPClient so callers
can supply a client whose transport enforces a dial-time resolved-IP guard
and redirect policy. Existing constructors delegate with the prior default
(30s timeout), so this is backward compatible — the guard itself lives in
the consuming server (e.g. brill-api/pkg/prime), not in this client lib.
Add godoc to Create and CreateBulk explaining they return immediately
without waiting for block inclusion. Update package-level example to show
both fire-and-forget and wait-for-block patterns. Add Transaction Modes
section to README with code examples.
Enable request timeout and cancellation control by adding context.Context
as the first parameter to all SDK API methods. This allows users to:
- Set per-request timeouts
- Cancel in-flight requests
- Pass request-scoped values
