feat: make policy length limits configurable per engine (#624)

- 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.
- Add bindings for C, C++, Python, WASM/JS, Java, Ruby, C#, Go

bindings/python/test.py

@@ -10,6 +10,8 @@ if hasattr(sys.stdout, "reconfigure"):
 engine = regorus.Engine()
 
 engine.set_rego_v0(True)
+# Raise the default col limit to 2000
+engine.set_policy_length_config(max_col=2000, max_file_bytes=1048576, max_lines=20000)
 
 # Load policies
 pkg = engine.add_policy_from_file('../../tests/aci/framework.rego')