v0.1.6: security/correctness/robustness hardening Iterative appsec + quality/perf/gap audit closure (converged after 5 review passes). Fixes untrusted-input crashes, memory-safety bugs, unbounded-work DoS, and validation bypasses across the parser, tokenizer, number, regex, CBOR, time, jsonpath, jsonld, unmarshal, parallel, patch, schema, emitter/encode, and async modules. 466 tests pass in Debug/ReleaseSafe/ReleaseFast/ReleaseSmall.