Support AW generated-CLI single-source boundary needs

[rickardvh]

Upstream/supporting umbrella for Agentic Workspace generated-command single-source work.

Current status

This issue has been decomposed by later, more precise work:

• command-generation Support target extensions and IR-derived conformance as reusable generated-code machinery #14/Add target extension contract #17: target-extension and conformance contract boundary.
• command-generation Build and release semver package artifacts #16: semver package artifacts and release metadata.
• command-generation Add TypeScript direct operation callable and function conformance target #18: reusable TypeScript direct callable/function-conformance support.
• [Workspace]: Make operation and test IR the single source of truth for generated implementations agentic-workspace#1476 lanes: AW-side operation/test IR migration, wrapper demotion, and guardrails.

Keep this issue open only as a slim umbrella for remaining package-generic support capabilities that are not already owned by those issues.

Remaining candidate support areas

• Generic freshness/fingerprint APIs for rendered outputs and source inputs, if not fully covered by Build and release semver package artifacts #16 release metadata.
• Primitive registry metadata that helps hosts distinguish portable primitives, host primitives, unsupported targets, and ownership evidence.
• Cross-target conformance helpers not already covered by Add target extension contract #17 or Add TypeScript direct operation callable and function conformance target #18.
• Generator/runtime comments or sentinels that discourage direct edits to generated outputs and route behavior changes to IR/generator primitives.

Acceptance

• Any remaining capability is package-generic and kept out of AW host-specific policy.
• Each implemented capability names which downstream AW lane or issue consumes it.
• Tests use non-AW fixtures where possible.
• If all remaining capability needs are owned by Build and release semver package artifacts #16/Add TypeScript direct operation callable and function conformance target #18/Add a non-AW command package fixture to prove generator portability #3/Support target-scoped generated command package resource projection #4 or AW #1476 lanes, this umbrella can be retired with links instead of kept as an implementation prompt.

Out of scope

• Repeating target-extension work from Add target extension contract #17.
• Repeating release artifact work from Build and release semver package artifacts #16.
• Repeating TypeScript direct callable/conformance work from Add TypeScript direct operation callable and function conformance target #18.
• AW-specific product behavior or policy.

[rickardvh]

Retiring this umbrella as decomposed into precise package-generic owners. Release artifacts and version metadata are owned by #16 / PR #20. TypeScript direct callable/function conformance is complete in #18. Non-AW portability and target-scoped package resources are owned by #3 and #4 / PR #21. Remaining AW host policy is downstream in agentic-workspace issues, not a command-generation implementation prompt. Keeping this umbrella open would invite duplicate work rather than add a missing package-generic capability.