feat: Go Runnable agent after Python contract qualification #1

Outcome and current status — 13 September 2026

This is the Go-language delivery umbrella. Generation is merged; executable delivery is not complete. PR #3, merge 8754b753a6ee72da37e6d74ca2f7053b20797193, delivered the agent distribution identity, handler scaffold and contract-generated Go bindings. There is no executable agent/harness/native builder or published release yet.

Continue the executable implementation and its acceptance in #2. Do not start a second agent implementation from this issue. Keep this umbrella open until that delivery is complete; merging the generation slice did not complete it.

Delivered and remaining

• Repository, codefly:runnable / go identity and runnable-go distribution prefix.
• Go handler scaffold and bounded schema bindings, including signed 64-bit integers and distinct optional/null states; generated code compiles and its presence/value cases are exercised.
• Executable gRPC Builder, shared invocation harness, dependency/toolchain preparation and measured native package: tracked in #2.
• Matching Python/Go contract cases and real TaskService native/k3d acceptance: tracked in #2 with CLI #638 and runtime #63.
• Compatible distribution/release and retained Markdown milestone.

Core #471/#473/#474 are merged. Python #3 and CLI #641 provide an implemented real gRPC path, but their pins still precede #474's final protocol fixes. Follow Python #1 through final-contract alignment and durable native/k3d qualification before claiming Go parity. The shared type no longer needs invention.

Go tooling, templates and harness belong here; generated owner handlers remain in the owner workspace. CLI communicates through gRPC, owns generic process supervision and image build/publish; Orchestration owns installation, tasks, invocation records and recovery. Adding Go must require no language-name dispatch in CLI/core/runtime. Agent image support emits recipes only.

The first Python/native/k3d milestone still precedes Go execution delivery and domain adoption. Supported facilities come from the declaration; placement comes from an installed deployment binding. Core currently supports native and Kubernetes Jobs, not a Lambda Runnable facility.