proof(L2): Tier 6 — external parameter/return profile widening (bytes, string, arrays, tuples, multi-returns)

[Th0rgal]

Child of #1723 (Tier 6). Final step to full EDSL coverage; depends on the ABI library from Tier 3 (#2082).

Goal

Widen SupportedExternalParamType (currently uint256, int256, uint8, address, bytes32, bool) to all ParamType constructors (bytes, string, array, fixedArray, tuple), and SupportedExternalReturnProfile to multi-value and dynamic returns.

Each new parameter type needs: ABI decoding correctness from calldata, ABI encoding correctness for returns, and composition with the dispatch theorem.

Done when

• SupportedExternalParamType accepts all ParamType constructors
• SupportedExternalReturnProfile accepts all return configurations
• 0 sorry, make check green