Add generalized tile presentation

[xtraid]

Summary

• add a pure isolated semantic module that freezes the exact Yang–Zhang 14-to-23 mapping and guards the canonical 23-tile table
• recognize only complete, correctly oriented, adjacent, and non-overlapping compositions while keeping singleton V1 instances and paper/internal glue labels explicit
• add three opt-in square-only views with deterministic goldens: the generalized 14-tile sheet, labelled atomic 23-tile legend, and generalized witness overlay

Scope

Presentation-only renderer packet. It does not change the root model, TILESET, solution schema, solvers, or the default square and hex render paths. The generalized views reject --hex rather than inventing generalized hex semantics.

Validation

• focused generalized presentation: 21 passed
• isolated renderer suite: 283 passed
• make check: 151 Python tests and 17 C test binaries
• strict GCC and Clang, sanitizers, static analyzer, Memcheck, and applicable Cachegrind checks
• informative coverage unchanged; 2,000-run parser fuzz smoke; dossier pdfLaTeX smoke; Pages/Jekyll checks
• diff, file modes, secrets, and generated-artifact checks
• two independent final review passes with no open findings