ci(governance): non-blocking drift check for check-ts-allowlist .affine/.deno.js (closes #312)

After #311 swapped the workflow to executing the committed `.deno.js`
artifact, the .affine source can silently drift if a maintainer edits
it without recompiling. This adds:

- `just check-ts-allowlist-drift` recipe — invokes the AffineScript
  compiler against the .affine source into a temp file and diffs
  against the committed .deno.js. Exit 0 = in sync.
- Non-blocking `continue-on-error: true` CI step in
  governance-reusable.yml that runs the same diff and surfaces a
  `::warning::` on drift. Skipped gracefully when the AffineScript
  compiler isn't on the runner (notice, exit 0).
- Pointer comment in check-ts-allowlist.affine header so maintainers
  see the drift recipe at the obvious place.

Non-blocking until the compiler output is hash-pinned per compiler
version — the compiler currently stamps a moving "Generated by
AffineScript compiler" header. Promotion to blocking is a separate
follow-up.

Closes #312

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.github/workflows/governance-reusable.yml

@@ -199,6 +199,33 @@ jobs:
         # the .ts is a separate follow-up after the dual-target window.
         run: deno run --allow-read --no-lock .standards-checkout/scripts/check-ts-allowlist.deno.js
 
+      - name: check-ts-allowlist source/compile drift (informational)
+        # Non-blocking — informational until the AffineScript compiler
+        # output is hash-pinned per compiler version. The compiler header
+        # currently stamps "Generated by AffineScript compiler" which is
+        # a moving target as the codegen evolves, so spurious diff =
+        # "compiler bumped" vs real diff = "someone edited .affine
+        # without recompiling". Promotion to blocking is gated on a
+        # compiler-version pin landing (see standards#312).
+        continue-on-error: true
+        run: |
+          if ! command -v affinescript >/dev/null 2>&1; then
+            echo "::notice::affinescript compiler unavailable on runner — skipping drift check"
+            exit 0
+          fi
+          tmp="$(mktemp /tmp/check-ts-allowlist-drift.XXXXXX.deno.js)"
+          if ! affinescript compile --deno-esm -o "$tmp" .standards-checkout/scripts/check-ts-allowlist.affine; then
+            echo "::warning::affinescript compile failed — drift check skipped"
+            rm -f "$tmp"
+            exit 0
+          fi
+          if diff -u .standards-checkout/scripts/check-ts-allowlist.deno.js "$tmp"; then
+            echo "✅ check-ts-allowlist .affine source and .deno.js compiled output are in sync"
+          else
+            echo "::warning::check-ts-allowlist.deno.js drifted from check-ts-allowlist.affine — re-run \`just check-ts-allowlist-drift\` locally and recommit the .deno.js"
+          fi
+          rm -f "$tmp"
+
       # Shared escape hatch for the banned-language-file checks below.
       # Honours three exemption mechanisms (see
       # standards/docs/EXEMPTION-MECHANISMS.adoc):

Justfile

@@ -125,6 +125,19 @@ help-me:
     @echo "Include the output of 'just doctor' in your report."
 
 
+# Verify scripts/check-ts-allowlist.deno.js matches what compiling
+# scripts/check-ts-allowlist.affine produces. Run after editing the
+# .affine source. Exit 0 = in sync; non-zero with diff = drifted.
+# See standards#312.
+check-ts-allowlist-drift:
+    @command -v affinescript >/dev/null 2>&1 || { echo "affinescript compiler not on PATH — skipping drift check"; exit 0; }
+    @tmp="$$(mktemp /tmp/check-ts-allowlist-drift.XXXXXX.deno.js)"; \
+      affinescript compile --deno-esm -o "$$tmp" scripts/check-ts-allowlist.affine; \
+      diff -u scripts/check-ts-allowlist.deno.js "$$tmp"; \
+      rc=$$?; \
+      rm -f "$$tmp"; \
+      exit $$rc
+
 # Print the current CRG grade (reads from READINESS.md '**Current Grade:** X' line)
 crg-grade:
     @grade=$$(grep -oP '(?<=\*\*Current Grade:\*\* )[A-FX]' READINESS.md 2>/dev/null | head -1); \

scripts/check-ts-allowlist.affine

@@ -5,6 +5,12 @@
 //
 // Step 2 of the estate-wide TypeScript → AffineScript migration campaign
 // (hyperpolymath/standards#239 umbrella, #241 tail-batch-1 issue).
+//
+// Compiled output: scripts/check-ts-allowlist.deno.js (committed). After
+// editing this file, re-run `just check-ts-allowlist-drift` to verify the
+// committed .deno.js matches what compiling this source produces. The
+// governance reusable runs the same check in CI as a non-blocking
+// informational step (standards#312).
 
 use Deno::{
   readTextFile, walkRecursive, exit, consoleError,