Refactor: migrate pdf_parser.py to golang (#16323)

### What problem does this PR solve?

Http API based on onnx model.
pdf_parser.py to golang

### Type of change

- [x] Refactoring

.pre-commit-config.yaml

@@ -17,3 +17,9 @@ repos:
       - id: ruff
         args: [ --fix ]
       - id: ruff-format
+
+  # TODO: re-enable go-fmt after PR merges to avoid formatting unrelated files
+  # - repo: https://github.com/dnephin/pre-commit-golang
+  #   rev: v0.5.1
+  #   hooks:
+  #     - id: go-fmt