fix(tests): stop e2e:updateSnaps swallowing its filter, and rebuilding twice

Two papercuts hit while regenerating baselines for the fix in this PR:

- vitest declares the flag as `-u, --update [type]` - an *optional* value,
  which also accepts `new`/`all`/`none`. So in `--run -u <filter>`, cac
  reads <filter> as the value of `-u`: the filter is dropped and the whole
  suite silently runs in update mode. `e2e:updateSnaps` ended in `-u`, so
  any filter a caller appends (as CLAUDE.md instructs) landed in exactly
  that trap - which quietly rewrote an unrelated, flaky
  `deleteShallowerBlock` baseline to a wrong value. Attaching the value as
  `--update=true` makes it unambiguous, so filters stay filters.

- wasm-pack emits `packages/xl-typst-compiler/pkg/package.json`, which the
  image content hash globbed, so building the wasm that docker-run.sh
  itself requires invalidated the image. A fresh clone paid two full image
  builds. `pkg` is now pruned alongside `dist`.

Author: YousefED

.claude/skills/testing-skill/SKILL.md

@@ -55,7 +55,7 @@ bash tests/docker-run.sh -e CI=1 -- --run [filters]
 
 A specific test file may be targeted by appending (part of) its name as a filter. A single browser may be targeted with `--project "e2e (chromium)"`. Individual tests in a file may be disabled using `skip`, i.e. `test.skip("Test name", ...)` (remember to revert this once all tests pass).
 
-Screenshot baselines can be regenerated with the `-u` argument, which must come **after** the filters (`--run <filters> -u`): written as `--run -u <filter>`, the filter is parsed as the flag's value and the **whole** suite runs in update mode, silently rewriting unrelated baselines. Note that `-u` only rewrites baselines whose comparison **fails** — a small intended change (e.g. a short text edit) that fits inside the suite's 2% pixel tolerance leaves the baseline stale while the test passes. To force a fresh capture, delete the baseline file first. Baselines are per-browser (`<name>-<browser>-linux.png`); after regenerating, always inspect the images before committing them.
+Screenshot baselines can be regenerated with `--update=true` (as `e2e:updateSnaps` does). Always attach the value: vitest declares the flag as `-u, --update [type]` (it also accepts `new`/`all`/`none`), so a bare `-u` before a filter swallows the filter as its value and silently runs the **whole** suite in update mode. `--update=true` cannot, so filters stay filters in any position. Note that `-u` only rewrites baselines whose comparison **fails** — a small intended change (e.g. a short text edit) that fits inside the suite's 2% pixel tolerance leaves the baseline stale while the test passes. To force a fresh capture, delete the baseline file first. Baselines are per-browser (`<name>-<browser>-linux.png`); after regenerating, always inspect the images before committing them.
 
 When testing a visual change, prefer writing screenshots to verify that the change is working as expected.
 

package.json

@@ -27,7 +27,7 @@
     "install-playwright": "cd tests && vp exec playwright install --with-deps",
     "e2e:image": "bash tests/docker-build.sh",
     "e2e": "bash tests/docker-run.sh -e CI=1 -- --run",
-    "e2e:updateSnaps": "bash tests/docker-run.sh -e CI=1 -- --run -u",
+    "e2e:updateSnaps": "bash tests/docker-run.sh -e CI=1 -- --run --update=true",
     "e2e:report": "serve -l 4173 tests/playwright-report",
     "lint": "vp lint --type-aware",
     "typecheck": "tsc --noEmit -p tsconfig.json",

tests/docker-run.sh

@@ -29,7 +29,10 @@ entrypoint_args=("$@")
 # Auto-rebuild the image if its content hash label doesn't match the current
 # repo state. The hash covers every file that affects the image's contents: the
 # Dockerfile itself, plus everything it bakes in — the lockfile, workspace file,
-# all package.json files, patches, and example sources. When they differ the
+# all package.json files, patches, and example sources. Generated output dirs
+# are pruned: `pkg/` is wasm-pack's, and it emits a package.json, so without
+# that prune, building the wasm this script *requires* would itself invalidate
+# the image and force a second full rebuild. When they differ the
 # image is rebuilt in place
 # (Docker's layer cache makes this fast when only a leaf changed).
 _dep_files() {
@@ -42,7 +45,8 @@ _dep_files() {
     find . -name package.json \
       -not -path '*/node_modules/*' \
       -not -path '*/.git/*' \
-      -not -path '*/dist/*'
+      -not -path '*/dist/*' \
+      -not -path '*/pkg/*'
   } | sort -u
 }
 _content_hash() {