feat: make policy length limits configurable per engine

[antmhs]

Trying to update to the latest regorus version pulled in #531 which broke some things on my end. This change makes it so the policy length limits are configurable (the limits from #531 are still the default, though).

Implemented:

• Add PolicyLengthConfig struct with max_col, max_file_bytes, and max_lines fields, replacing hardcoded constants in the lexer.
• Add Engine::set_policy_length_config and clear_policy_length_config to allow callers to override the default limits.
• Add Source::from_contents_with_limits and from_file_with_limits for direct Source construction with custom limits; existing from_contents and from_file signatures are preserved using defaults.
• Add tests for default rejection, custom limits, and engine plumbing.

[antmhs]

@microsoft-github-policy-service agree company="Amazon"

[anakrish]

@antmhs Thanks for the contribution.

It would be worth adding a comment in new_from_compiled_policy that since compiled policies are already parsed, they don't need length limit config.

[antmhs]

I added setters to Parser and Lexer instead since I saw that that's how the Rego V0 field is passed too. Also, the constructors are already used in a few places in the examples directory.

[anakrish]

@antmhs Looks good. Some more feedback about comments and test.

Ideally, we would want to also expose this new config to bindings. But we can do that in a second PR. Are you primarily a Rust based client? Another user from Amazon was mainly Java based.

[antmhs]

Updated the comments and added the test for max_col. We are using both Java and Rust. Anyway, I added the new config to all bindings:

• C and C++ use a struct for the config
• C# uses a struct for the config
• Go uses a struct for the config
• Java uses a class with public fields for the config (I saw that's how it's done for other classes in the other bindings, but this is not very idiomatic Java. Ideally, you would have getters and maybe a builder)
• Python uses keyword-only args for the config
• Ruby uses a dict for the config (also, I fixed the Ruby build since it was failing after b4a69a1 which bumped serde_magnus from 0.9 to 0.11 which introduced a breaking change since deserialization now requires passing the Ruby object)
• JS through WASM uses a JS object for the config (I also added a dependency on serde-wasm-bindgen for deserializing)

[anakrish]

@antmhs Thank you so much for taking care of bindings as well! Just couple more comments.

[antmhs]

Addressed the comments. Also, the workflow was failing because the column width was lowered to 200 in the bindings, now it's 2000 which should pass.

[antmhs]

Missed one config in bindings/c/main.c.

[anakrish]

LGTM. Thank you for the contribution!