Implement Phase 9: client libraries (Go, Rust, Lisp, Python)

- clients/README.md: canonical API surface and error type reference
- clients/testdata/: shared JSON response fixtures
- clients/go/: mciasgoclient package; net/http + TLS 1.2+; sync.RWMutex
  token state; DisallowUnknownFields on all decoders; 25 tests pass
- clients/rust/: async mcias-client crate; reqwest+rustls (no OpenSSL);
  thiserror MciasError enum; Arc<RwLock> token state; 22+1 tests pass;
  cargo clippy -D warnings clean
- clients/lisp/: ASDF mcias-client; dexador HTTP, yason JSON; mcias-error
  condition hierarchy; Hunchentoot mock-dispatcher; 37 fiveam checks pass
  on SBCL 2.6.1; yason boolean normalisation in validate-token
- clients/python/: mcias_client package (Python 3.11+); httpx sync;
  py.typed; dataclasses; 32 pytest tests; mypy --strict + ruff clean
- test/mock/mockserver.go: in-memory mock server for Go client tests
- ARCHITECTURE.md §19: updated per-language notes to match implementation
- PROGRESS.md: Phase 9 marked complete
- .gitignore: exclude clients/rust/target/, python .venv, .pytest_cache,
  .fasl files
Security: token never logged or exposed in error messages in any library;
TLS enforced in all four languages; token stored under lock/mutex/RwLock

clients/rust/target/debug/.fingerprint/mcias-client-815b09c6645ffc29/test-lib-mcias_client.json

@@ -0,0 +1 @@
+{"rustc":16243257175721966122,"features":"[]","declared_features":"[]","target":16728153861312901355,"profile":15057526963834790232,"path":10763286916239946207,"deps":[[2448563160050429386,"thiserror",false,1609615225369714410],[8333724820698747522,"wiremock",false,11475196584943952752],[13298363700532491723,"tokio",false,634726864496810915],[13548984313718623784,"serde",false,16120970927335062175],[13795362694956882968,"serde_json",false,4117845875591086358],[17325453097244291330,"reqwest",false,14099176340486706190]],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/mcias-client-815b09c6645ffc29/dep-test-lib-mcias_client","checksum":false}}],"rustflags":[],"config":2069994364910194474,"compile_kind":0}