diff --git a/.github/scripts/tests/apply-repo-settings-workflow.bats b/.github/scripts/tests/apply-repo-settings-workflow.bats
index 28d8eb2a..446183e8 100644
--- a/.github/scripts/tests/apply-repo-settings-workflow.bats
+++ b/.github/scripts/tests/apply-repo-settings-workflow.bats
@@ -2,12 +2,16 @@
 # Tests for .github/workflows/apply-repo-settings.yml — static YAML assertions,
 # no live API calls.
 #
+# This workflow is now a THIN CALLER STUB synced from the org source of truth
+# (petry-projects/.github/standards/workflows/apply-repo-settings.yml). All
+# settings/ruleset logic — including the #420 GH_TOKEN preflight guard — moved
+# into the org reusable workflow (apply-repo-settings-reusable.yml); the consumer
+# repo carries no script copy and the caller job has no steps. These tests were
+# rewritten to pin the stub contract instead of the retired inline job.
+#
 # Regression guard for issue #403 (ruleset-drift-pr-quality-require_last_push_approval):
-# the codified pr-quality ruleset already sets require_last_push_approval: true, but the
-# live ruleset kept drifting back to false because apply-repo-settings.yml only re-applied
-# the codified standard on manual dispatch or on a push touching the ruleset scripts.
-# A scheduled trigger makes the codified rulesets self-heal drift automatically. These
-# tests pin that the schedule trigger exists and that the pre-existing triggers survive.
+# a scheduled trigger makes the codified rulesets self-heal live drift automatically.
+# The schedule/workflow_dispatch guards below survive the migration to the stub.
 
 WORKFLOW="$(cd "$(dirname "$BATS_TEST_FILENAME")/../../.." && pwd)/.github/workflows/apply-repo-settings.yml"
 
@@ -36,52 +40,50 @@ WORKFLOW="$(cd "$(dirname "$BATS_TEST_FILENAME")/../../.." && pwd)/.github/workf
   [ "$output" = "true" ]
 }
 
-@test "workflow preserves the push trigger on main touching the ruleset scripts" {
+@test "workflow preserves the push trigger on main touching the stub itself" {
   run yq '.on.push.branches[0]' "$WORKFLOW"
   [ "$status" -eq 0 ]
   [ "$output" = "main" ]
 
-  run yq '.on.push.paths | contains([".github/scripts/apply-pr-quality-ruleset.sh"])' "$WORKFLOW"
+  # The stub carries no script copy, so it re-applies on a push to its own file.
+  run yq '.on.push.paths | contains([".github/workflows/apply-repo-settings.yml"])' "$WORKFLOW"
   [ "$status" -eq 0 ]
   [ "$output" = "true" ]
 }
 
-# Regression guard for issue #420 (ruleset-drift-pr-quality-require_last_push_approval
-# recurred after #403). The #403 schedule cannot self-heal drift because every run —
-# including the scheduled one — fails immediately with "GH_TOKEN is required": the
-# GH_TOKEN_ADMIN secret is not configured, and the failure was buried in the script
-# log where nobody noticed. These tests pin a preflight step that surfaces the missing
-# secret loudly (GitHub error annotation + job summary) with actionable remediation, so
-# the operational blocker is discoverable instead of silently recurring.
+# Thin-caller-stub contract: the job delegates to the org reusable workflow and
+# carries no inline steps of its own (settings/ruleset logic lives upstream).
 
-@test "workflow has a preflight step that verifies GH_TOKEN_ADMIN before applying (issue #420)" {
-  run yq '[.jobs["apply-settings"].steps[] | select(.env.GH_TOKEN_ADMIN != null and ((.run // "") | test("GH_TOKEN_ADMIN")))] | length' "$WORKFLOW"
+@test "apply job delegates to the org reusable workflow via uses:" {
+  run yq '.jobs.apply.uses' "$WORKFLOW"
   [ "$status" -eq 0 ]
-  [ "$output" -ge 1 ]
+  [ "$output" != "null" ]
+  printf '%s\n' "$output" | grep -q 'petry-projects/.github/.github/workflows/apply-repo-settings-reusable.yml@'
+}
+
+@test "apply job carries no inline steps (logic lives in the reusable)" {
+  run yq '.jobs.apply | has("steps")' "$WORKFLOW"
+  [ "$status" -eq 0 ]
+  [ "$output" = "false" ]
 }
 
-@test "preflight step surfaces the missing secret loudly and actionably (issue #420)" {
-  run yq '.jobs["apply-settings"].steps[] | select(.env.GH_TOKEN_ADMIN != null and ((.run // "") | test("GH_TOKEN_ADMIN"))) | .run' "$WORKFLOW"
+@test "apply job inherits secrets so the reusable gets the admin token" {
+  run yq '.jobs.apply.secrets' "$WORKFLOW"
   [ "$status" -eq 0 ]
-  local preflight="$output"
-  # emits a GitHub error annotation so the failure is visible on the run page
-  printf '%s\n' "$preflight" | grep -q '::error'
-  # writes actionable remediation to the job summary
-  printf '%s\n' "$preflight" | grep -q 'GITHUB_STEP_SUMMARY'
-  # fails the job so the drift is not silently left unhealed
-  printf '%s\n' "$preflight" | grep -q 'exit 1'
+  [ "$output" = "inherit" ]
 }
 
-@test "preflight runs before the apply-repo-settings step (issue #420)" {
-  run yq '.jobs["apply-settings"].steps | to_entries | map(select(.value.env.GH_TOKEN_ADMIN != null and ((.value.run // "") | test("GH_TOKEN_ADMIN")))) | .[0].key' "$WORKFLOW"
+@test "checkout_ref forward stays in lockstep with the uses: channel pin" {
+  run yq '.jobs.apply.with.checkout_ref' "$WORKFLOW"
   [ "$status" -eq 0 ]
-  local preflight_idx="$output"
+  local checkout_ref="$output"
+  [ "$checkout_ref" != "null" ]
+  [ -n "$checkout_ref" ]
 
-  run yq '.jobs["apply-settings"].steps | to_entries | map(select((.value.run // "") | test("apply-repo-settings.sh"))) | .[0].key' "$WORKFLOW"
+  run yq '.jobs.apply.uses' "$WORKFLOW"
   [ "$status" -eq 0 ]
-  local apply_idx="$output"
+  local uses="$output"
 
-  [ -n "$preflight_idx" ] && [ "$preflight_idx" != "null" ]
-  [ -n "$apply_idx" ] && [ "$apply_idx" != "null" ]
-  [ "$preflight_idx" -lt "$apply_idx" ]
+  # `uses:` ends with @<channel-tag>; checkout_ref must equal that same tag.
+  [ "${uses##*@}" = "$checkout_ref" ]
 }
diff --git a/.github/workflows/apply-repo-settings.yml b/.github/workflows/apply-repo-settings.yml
index 0c39f617..4c983ba3 100644
--- a/.github/workflows/apply-repo-settings.yml
+++ b/.github/workflows/apply-repo-settings.yml
@@ -1,71 +1,55 @@
-# Apply repository settings — disables check-suite auto-triggers (including
-# Claude app 1236702) that permanently block auto-merge, and enforces all other
-# required settings from standards/github-settings.md.
+# ─────────────────────────────────────────────────────────────────────────────
+# SOURCE OF TRUTH: petry-projects/.github/standards/workflows/apply-repo-settings.yml
+# Standard:        petry-projects/.github/standards/github-settings.md
+#                  petry-projects/.github/standards/ruleset-remediation-runbook.md
+# Reusable:        petry-projects/.github/.github/workflows/apply-repo-settings-reusable.yml
 #
-# Triggers:
-#   • workflow_dispatch — manual run to fix current state immediately
-#   • push to main on the settings script — re-applies on every future change
-#   • schedule — weekly re-apply so codified rulesets self-heal live drift.
-#     Without this, a ruleset that is manually changed in the GitHub UI (e.g.
-#     pr-quality's require_last_push_approval flipped to false) stays drifted
-#     until someone edits a script path, which is why compliance drift findings
-#     recurred (#325 → #403). The apply scripts are idempotent, so re-running is
-#     safe.
+# AGENTS — READ BEFORE EDITING:
+#   • This file is a THIN CALLER STUB. All settings/ruleset logic lives in the
+#     reusable workflow above; consumer repos carry NO script copy.
+#   • You MAY change: the cron offset only (stagger org API load).
+#   • You MUST NOT change: the `uses:` line, `secrets: inherit`, the job-level
+#     `permissions:` block, or the `checkout_ref` forward — reusable workflows can
+#     be granted no more permissions than the calling job has, and forwarding an
+#     input the pinned channel does not declare breaks every run at startup (#1034).
+#   • If you need different behaviour, open a PR against the reusable in the
+#     central repo.
+# ─────────────────────────────────────────────────────────────────────────────
 #
-# Required secret: GH_TOKEN_ADMIN — a classic PAT or fine-grained token with
-#   administration:write (repo admin) scope for petry-projects/markets.
+# Apply repo settings — thin caller for the org-level compliance self-heal.
+# To adopt: copy this file verbatim to .github/workflows/apply-repo-settings.yml.
+# Required org secret (inherited):
+#   GH_PAT_DON_PETRY — classic PAT, repo scope, owner has admin on this repo.
 name: Apply repo settings
 
 on:
-  workflow_dispatch:
   schedule:
-    - cron: "23 5 * * 1"
+    # Weekly self-heal. The cron offset MAY be changed to stagger org API load.
+    - cron: '17 6 * * 1'
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: "Preview changes without applying"
+        type: boolean
+        required: false
+        default: false
   push:
     branches: [main]
     paths:
-      - .github/scripts/apply-repo-settings.sh
-      - .github/scripts/apply-code-quality-ruleset.sh
-      - .github/scripts/apply-pr-quality-ruleset.sh
-      - .github/workflows/apply-repo-settings.yml
+      - '.github/workflows/apply-repo-settings.yml'
 
 permissions: {}
 
+concurrency:
+  group: apply-repo-settings
+  cancel-in-progress: false
+
 jobs:
-  apply-settings:
-    name: Apply repo settings
-    runs-on: ubuntu-latest
+  apply:
     permissions:
       contents: read
-    steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-
-      # Preflight — without GH_TOKEN_ADMIN the apply step dies with a generic
-      # "GH_TOKEN is required" buried in the script log, so the weekly self-heal
-      # fails unnoticed and ruleset drift recurs (#325 → #403 → #420). Surface the
-      # missing secret loudly (error annotation + job summary) so it gets fixed.
-      - name: Verify admin token is configured
-        env:
-          GH_TOKEN_ADMIN: ${{ secrets.GH_TOKEN_ADMIN }}
-        run: |
-          if [ -z "${GH_TOKEN_ADMIN}" ]; then
-            {
-              echo "## Apply repo settings cannot run"
-              echo ""
-              echo "The \`GH_TOKEN_ADMIN\` secret is not configured for this repository."
-              echo "Without it the pr-quality / code-quality rulesets cannot self-heal, so"
-              echo "compliance drift (e.g. \`require_last_push_approval\` flipping to false)"
-              echo "recurs unnoticed."
-              echo ""
-              echo "**Fix:** provision a repo/org admin token secret named \`GH_TOKEN_ADMIN\`"
-              echo "with \`administration:write\` scope (see standards/github-settings.md),"
-              echo "then re-run this workflow."
-            } >> "$GITHUB_STEP_SUMMARY"
-            echo "::error title=GH_TOKEN_ADMIN missing::Provision the GH_TOKEN_ADMIN secret so ruleset drift can self-heal (see job summary)."
-            exit 1
-          fi
-          echo "GH_TOKEN_ADMIN is configured."
-
-      - name: Apply repo settings
-        env:
-          GH_TOKEN: ${{ secrets.GH_TOKEN_ADMIN }}
-        run: bash .github/scripts/apply-repo-settings.sh
+    uses: petry-projects/.github/.github/workflows/apply-repo-settings-reusable.yml@apply-repo-settings/v1-ring1  # NOSONAR(githubactions:S7637) first-party channel ref
+    with:
+      dry_run: ${{ github.event_name == 'workflow_dispatch' && inputs.dry_run == true }}
+      checkout_ref: apply-repo-settings/v1-ring1  # keep in lockstep with the uses: channel pin
+    secrets: inherit  # NOSONAR(githubactions:S7635) first-party trusted reusable