* tests: add initial test suite with binary I/O, StringHelper, and CRC64 tests
Adds CMake infrastructure (LUS_BUILD_TESTS option) and three test files
covering BinaryReader/Writer round-trips, StringHelper utilities, and
CRC64 hashing. Also switches prism to a fork that guards its CTest
registration behind PRISM_STANDALONE to prevent leaking into consumers.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* ci: add test-validation workflow
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>