Add enum ranges to echidna printer output

[ep0chzer0]

Summary

Fixes #1203

Adds enum range information to the echidna printer output to help Echidna generate valid calldata for enum parameters. Since enums are converted to uint256 in the ABI, Echidna needs to know the valid range to avoid producing invalid calldata.

Changes

• Added _extract_enum_ranges() function that extracts enum definitions from contracts
• Added enum_ranges field to the echidna printer JSON output

Example Output

{
  "enum_ranges": {
    "MyContract": {
      "Status": 4,
      "Priority": 3
    }
  }
}

This indicates:

• Status enum has 4 valid values (0, 1, 2, 3)
• Priority enum has 3 valid values (0, 1, 2)

Test Plan

• Verify enum extraction works for contracts with enums
• Verify output format matches expected JSON structure
• Run black formatter

🤖 Generated with Claude Code

[ep0chzer0]

Hello maintainers! This adds enum range information to the echidna printer as requested in #1203. The implementation follows the format suggested in the issue. Could you please approve the CI workflows to run? Thank you!