fix(modules-12,14,15,18,19,25): editor note, refresh CI action pins, scaffold M15 merge

- M12: note the editor that `git revert -m 1 HEAD` opens (save/close, or --no-edit);
  the -m 1 / --no-ff merge teaching is unchanged.
- Refresh stale CI action pins to verified-current majors (actions/checkout @v4->@v7,
  actions/setup-python @v5->@v6; confirmed via GitHub Releases, 2026-06) across
  M14/M15/M18/M19/M25; add a Verify-before-publish item for pinned action versions.
- M15: scaffold the "slot security steps into the workflow" YAML merge (before/after
  diff, indentation caution, copy-whole-job alternative). Planted devices intact.

Closes #43
Closes #44
Closes #50

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TfzV5QvtPDz8LJS3Pu5VLT

modules/14-continuous-integration/README.md

@@ -119,9 +119,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out the code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.12"
       - name: Install tools
@@ -371,7 +371,7 @@ CI YAML and the actions it references drift faster than the rest of this durable
 Re-check at build time:
 
 - [ ] **Action versions.** Confirm `actions/checkout` and `actions/setup-python` major versions in
-      `ci-starter.yml` are current and not deprecated. Pinned majors (`@v4`, `@v5`) age.
+      `ci-starter.yml` are current and not deprecated. Pinned majors (`@v7`, `@v6`) age.
 - [ ] **Runner labels.** Confirm `ubuntu-latest` (and any GitLab `image:` tag) still resolves to a
       supported image; default runner OS versions roll forward.
 - [ ] **Trigger and config syntax.** Verify the `on:` keys and overall workflow schema against the

modules/14-continuous-integration/lab/ci-starter.yml

@@ -25,11 +25,11 @@ jobs:
     steps:
       # Step 1: get your code onto the runner. Without this the runner is empty.
       - name: Check out the code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       # Step 2: install the language the project needs. Pin a version so CI matches what you run.
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.12"