Extract renderer-ready bundled font records

[Happypig375]

Parent: #191

This is the parent tracker for converting #319's deterministic table artifacts into a complete renderer-ready logical font model. Production rendering remains unchanged until #321.

Sub-issues:

• Define the renderer-font record schema and deterministic writer #327 — versioned logical schema, deterministic writer, and standalone bounds-checked reader
• Extract cmap, metrics, bounds, and contours into font records #328 — cmap/fallback, metrics, advances, bounds, and complete contours
• Extract OpenType MATH constants, variants, and assemblies #329 — all OpenType MATH constants, corrections, variants, and assemblies
• Prove complete bundled-font record parity and representation equivalence #330 — exhaustive three-face parity, binary/generated-C# equivalence, sizes, and CI

Completion criteria:

• the ordered sub-issue chain is complete
• no raw SFNT parser is needed to consume the logical result
• source hashes from Prototype deterministic bundled-font artifact formats #319 and deterministic regeneration remain enforced
• every emitted glyph/outline/metric/MATH record is parity-checked against Typography/OpenFontReader
• intentionally unused data is documented with no silent loss