refactor(stf): consolidate block validation into compute_asm_transition

[prajwolrg]

Description

Move merkle root validation, witness commitment check, witness root computation, and transaction grouping from callers into the core STF function. This removes the AsmStfInput intermediary so callers pass bitcoin::Block and AuxData directly, ensuring validation happens in one place.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature/Enhancement (non-breaking change which adds functionality or enhances an existing one)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactor
• New or updated tests
• Dependency update
• Security fix

Notes to Reviewers

Checklist

• I have performed a self-review of my code.
• I have commented my code where necessary.
• I have updated the documentation if needed.
• My changes do not introduce new warnings.
• I have added tests that prove my changes are effective or that my feature works.
• New and existing tests pass with my changes.

Related Issues

[github-actions]

Commit: 101b794
SP1 Execution Results

program	cycles	success
ASM STF	533,229,433	yes