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

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

Start by locating the ACP-based Keeper workflow and the handling of concept-sets-approved/*.json. Trace how generated and approved concept sets are selected, reused, and overwritten, then identify where workflow state and prompts are maintained. Done means the review, keep, overwrite, and rerun choices are explicit, provenance is persisted, source status is clear, and regression tests cover reuse, overwrite, and rerun paths.