Implement Unicode 17 UAX #9 bidi analysis

[lukewilliamboswell]

Implements #39.

Summary

• adds retained Unicode 17.0.0 / UAX Updating headers of all files #9 rev. 51 paragraph analysis with P1-P3, X1-X10, W1-W7, N0-N2, I1-I2, and per-line L1-L4
• preserves original scalar identities, absolute byte/scalar ranges, X9 removal state, logical and visual runs, bracket pairing, mappings, and mirroring facts
• adds P1 paragraph ranges, range-aware analysis, typed limits/errors, and explicit per-line reordering
• registers and strictly parses the official Unicode 17 BidiTest and BidiCharacterTest files
• adds seeded metamorphic coverage, exhaustive bidi-property validation, allocation/scaling evidence, and examples
• provides an optional local SHA-pinned Unicode Code9 C differential command; no dedicated scheduled workflow is added
• minimizes and captures fuzz/differential failures as reusable regression artifacts