chore_supply_chain_pin_precommit_and_compose_images: Digest-pin pre-commit hooks and Compose service images

[github-actions]

Problem

Digest-pin pre-commit hooks and Compose service images

(Auto-created by reconcile-tracking-issues from the planned-feature folder — the
idea.md is the source of detail; run /idea-preflight to verify claims against the
current tree before execution.)

Status

• Stage: IDEA
• Priority: P2

Definition of done

• See the acceptance criteria in the linked idea.md (backfill this checklist at the SPEC stage).

Artifacts

• Idea: docs/00_overview/planned_features/04_ga/chore_supply_chain_pin_precommit_and_compose_images/idea.md

How to execute

Run /idea-preflight, then /pipeline docs/00_overview/planned_features/04_ga/chore_supply_chain_pin_precommit_and_compose_images --auto.