Add explicit concept-set approve/edit/rerun loop for ACP-based Keeper workflow

[rkboyce]

Title
Add explicit approve/edit/rerun loop for ACP-generated Keeper concept sets

Body

Problem

The ACP-based Keeper flow can now generate, reuse, and overwrite approved concept-set artifacts, but there is still no explicit human approval/edit/rerun loop in the workflow.

Manual edits to concept-sets-approved/*.json are consumable, but editing remains out-of-band.

Current behavior

• generated concept sets can seed approved concept sets
• approved concept sets can be reused
• approved concept sets can be overwritten from generated output
• there is no first-class approval state machine or in-shell review loop

Risk

• workflow remains operationally awkward
• users may accidentally rerun with stale or unreviewed concept sets
• approval provenance is weak

Requested change

Add an explicit approval/edit/rerun concept-set workflow for ACP-based Keeper.

Acceptance criteria

• users can clearly choose between:
  • review current generated concept sets
  • keep approved concept sets
  • overwrite approved from generated
  • rerun concept-set generation
• approval provenance is persisted in workflow state
• prompts/status make current approved/generated sources clear
• regression tests cover reuse, overwrite, and rerun paths