v0.0.0-8595-gf8ffc350c

Switch Yosys statistics parsing from text to JSON output.

The Yosys synthesis service now uses `yosys tee` to write the output of `yosys stat` to a JSON file. The `yosys_util` library has been updated to parse this JSON file using `json11` to extract cell counts, area, and sequential area, replacing the previous regex-based parsing of the standard output.

PiperOrigin-RevId: 802850205