refactor: use cardinal.EntityID directly in physics2d contact types

[AnthonyWadham]

TL;DR

Replace uint64 wire-format conversions for entity IDs with direct cardinal.EntityID usage in the physics2d contact tracking system.

What changed?

ContactPairEntry now stores cardinal.EntityID directly for EntityA and EntityB instead of uint64. The intermediate conversion functions (entityIDFromUint64) and associated bounds-checking logic have been removed, along with the corresponding uint64(...) casts when writing back to the component. lessContactPairByEndpoints now accepts cardinal.EntityID arguments natively, eliminating the explicit casts at call sites.

Why make this change?

The previous approach stored entity IDs as uint64 in the component struct and converted them to cardinal.EntityID (a uint32) at runtime, requiring explicit bounds checks to guard against silent truncation. Since cardinal.EntityID is the canonical type throughout the engine, using it directly removes unnecessary conversions, eliminates the risk of mismatched types, and simplifies the code without any loss of correctness.

[AnthonyWadham]

• refactor: use cardinal.EntityID directly in physics2d contact types #890 👈 (View in Graphite)
• main

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