add run_json to JqProgram

[williamcotton]

Description:

This PR introduces a new method run_json to JqProgram that allows executing jq filters directly against serde_json::Value inputs, bypassing the overhead of string serialization and parsing.

Currently, the crate requires users to serialize data to a JSON string before execution and parse the resulting string back into JSON. For high-throughput middleware or hot paths, this double-parsing (Rust -> String -> jq-internal -> String -> Rust) is a significant bottleneck.

Changes:

• Direct Marshaling: Implemented JV::from_serde and JV::to_serde to map serde_json::Value types directly to/from libjq's jv pointers via FFI.
• New API: Added JqProgram::run_json(&mut self, data: &serde_json::Value) -> Result<serde_json::Value>.
• Dependency Update: Promoted serde_json from [dev-dependencies] to [dependencies] to support these public API types.
• Integer Handling: Added logic to detect "whole number" floats returned by libjq (which treats all numbers as f64) and convert them to serde_json Integers. This ensures the output matches standard jq CLI behavior and prevents strict equality checks from failing in downstream Rust code.

Performance:

By eliminating the intermediate string allocation and parsing steps, this implementation significantly reduces CPU usage and memory churn.

• Latency: Removes the O(n) cost of string parsing for every request.

Safety:

• Utilized jv_copy during FFI conversions to correctly manage libjq reference counting and prevent double-free or use-after-free errors.
• Ensured error checking for jv_invalid states is performed correctly at the end of the iteration loop to prevent assertion failures in jv_invalid_has_msg.

Verification:

• Added unit tests covering basic types, complex nested structures, and deep recursion.
• Verified that integer inputs (42) are correctly returned as integers (42) rather than floats (42.0).
• Existing tests pass.