docs(map): record bounded codegen integration

[luisleo526]

Summary

Refresh the engine coverage documentation after pineforge-engine#122 and pineforge-codegen-oss#78 completed the bounded PineMap runtime/codegen integration.

• replace stale std::unordered_map / migration-pending claims
• document the supported string-key/primitive-value boundary and conservative fail-closed cases
• reclassify the map type plus 11 map.* functions from transpiler-only to runtime-backed
• keep the combined executable identifier total unchanged at 409/941
• pin the reconciled engine/codegen commits and current engine version

Validation

• exact 12-identifier delta reconciles to 193 Runtime / 216 Transpiler / 941 total
• claims checked against engine 06bb724 and codegen cefeec8
• independent cold documentation review GO after version and footnote corrections
• git diff --check

Documentation only; no runtime, generated output, validation tier, or score changes.