Expose match groups

[Divide-By-0]

Allow anyone to index regex matched groups as they normally would, map that to the relevant ispublic/isprivate states, then expose that automatically.

This will be needed for good UX and Javascript dev compatibility.

[brolag]

Proposal for Implementing Match Group Exposure in ZK Regex Circuits

• Implement a new function in packages/compiler/src/regex.rs:

  fn parse_regex_with_match_groups(regex: &str, public_groups: &[String]) -> DecomposedRegexConfig

• Update genFromDecomposed in packages/compiler/src/wasm.rs to accept regex with groups:

  pub fn genFromDecomposed(regex: &str, public_groups: &[String], circomTemplateName: &str) -> String

• Modify process_public_regex in packages/compiler/src/regex.rs to handle group structure.

• Add tests in packages/circom/tests/ for the new functionality.

• Update CLI in packages/compiler/src/main.rs to support the new input format.