feat: sharpen tip-1020 standard

[howydev]

I think a large reason to do this precompile is to allow smart contracts to forward compatibility with future Tempo account types

Changes:

1. verifyStateful should return keyId to allow the calling contract to further query scoped permissions of this key
2. Improved the gas model of the precompile and added clarification around cost
3. Improved invariants quality

I'm still not sold on exposing access keys in this interface; if anything, it feels like it should be a stateful function in the AccountKeychain precompile instead. IMO we should bundle that with TIP-1011

[github-actions]

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tempo-precompiles: minor
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Updated TIP-1020 (Signature Verification Precompile) spec with additional authors, expanded `verifyStateful` return type to include `keyId`, added Security Considerations section, improved gas cost documentation, restructured Compatibility and Invariants sections, and removed the Rationale section.

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