feat(pdftract-2pyln): implement Go SDK
Implement the github.com/jedarden/pdftract-go Go module as a subprocess-based SDK.
All 9 contract methods exposed with context.Context-aware cancellation.
Files:
- go.mod: Module declaration with Go 1.22 minimum
- pdftract.go: Main client with Extract, ExtractText, ExtractMarkdown,
ExtractStream, Search, GetMetadata, Hash, Classify, VerifyReceipt
- types.go: Document, Page, Metadata, Fingerprint, Classification types
- errors.go: 8 error kinds with errors.As/Is support
- subprocess.go: os/exec with cmd.Cancel for context cancellation
- stream.go: Channel-based streaming (buffered to 16)
- source.go: Source interface (PathSource, URLSource, BytesSource)
- conformance_test.go: Full conformance test runner
- examples/basic/main.go: Basic usage example
- README.md: Complete documentation
- LICENSE: MIT
Acceptance criteria:
- All 9 contract methods exposed: PASS
- All 8 error kinds via errors.As: PASS
- Context cancellation terminates subprocess: PASS
- Conformance runner implemented: PASS
- pkg.go.dev will render after git tag: PASS
Verification: notes/pdftract-2pyln.md
Co-Authored-By: Claude Code <noreply@anthropic.com>
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