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/icu_properties-a9c482805a236fa8/lib-icu_properties.json

@@ -0,0 +1 @@
+{"rustc":16243257175721966122,"features":"[\"compiled_data\"]","declared_features":"[\"alloc\", \"compiled_data\", \"datagen\", \"default\", \"serde\", \"unicode_bidi\"]","target":12882061015678277883,"profile":5347358027863023418,"path":18409733477355529301,"deps":[[3966877249195716185,"icu_locale_core",false,8738334886186839694],[5251024081607271245,"icu_provider",false,2722244296454231244],[5858954507332936698,"icu_properties_data",false,10090350442969559214],[6160379875186348458,"zerotrie",false,779555625856432278],[14324911895384364736,"icu_collections",false,4613497859368639558],[14563910249377136032,"zerovec",false,3103798927038060636]],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/icu_properties-a9c482805a236fa8/dep-lib-icu_properties","checksum":false}}],"rustflags":[],"config":2069994364910194474,"compile_kind":0}