chore(docker): keep the local fixtures and the stale harnesses out of the tree

docker/.gitignore

@@ -1,2 +1,10 @@
 .env
 data/
+
+# Local-only: test fixtures, plus copies of files already tracked at this
+# level (md/ mirrors the seven *.md beside it, old_film.png mirrors
+# frontend/public/assets/old_film.png byte for byte). They are needed on the
+# box that runs the checks, not in the history.
+/sample/
+/md/
+/old_film.png

docker/frontend/.gitignore

@@ -1,3 +1,10 @@
 node_modules/
 dist/
 public/wasm/
+
+# Stale one-off harnesses: each imports rawDevelop.ts from an older day, so a
+# run today dies on its missing ./skiaShim and ./tiffDecode imports. The
+# checks the repo carries are the *-check.mjs beside them.
+/scripts/test-all-raws.mjs
+/scripts/test-color-accuracy.mjs
+/scripts/test-extract-speed.mjs