exif-oxide

docs: add consistency best practices section to CODEGEN.md; outline guidelines for TagValue construction, function calls, string generation, and error handling

docs: enhance TPP guide clarity and emphasis on foundational documents; refine structure and instructions

feat: introduce P09 plan to eliminate TIMTOWTDI in code generation; standardize patterns and reduce inconsistencies

feat: add camera-specific mathematical functions for ExifTool compatibility; include tests for pow2, aperture, ISO, and string formatting helpers

feat: add debug statistics analyzer and integration tests for P07 impl_registry fallback; improve binary and normalized expression handling