ci: lint and typecheck the whole tree in CI and only staged files in the pre-commit hook

.gitattributes

@@ -1,4 +1,6 @@
 # Sourced by /bin/sh inside the Lite container image: CRLF would break it.
 *.envsh text eol=lf
+# Run by sh from Git Bash on Windows, which does not strip CR.
+.husky/* text eol=lf
 # Demo fixtures record exact byte sizes of these files; never normalise them.
 public/demo/** -text

.github/workflows/tests.yml

@@ -34,3 +34,28 @@ jobs:
         # from timing out on the shared runners; the longer per-test timeout
         # covers the jsdom-heavy suites.
         run: npx vitest run --pool=forks --maxWorkers=2 --testTimeout=15000
+
+  # The pre-commit hook lints only staged files and never runs on fork PRs,
+  # so this is the one place the whole tree is checked.
+  lint:
+    name: Lint and typecheck
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Typecheck
+        run: npm run typecheck
+
+      - name: Lint
+        run: npm run lint

.husky/pre-commit

@@ -1 +1,6 @@
-npx tsc --noEmit && npx eslint . --ext .ts,.tsx
+#!/bin/sh
+# Typecheck the project (incremental, a few seconds warm) and lint only the
+# staged files. The full lint and typecheck run in CI for every push and PR.
+npx tsc --noEmit || exit 1
+files=$(git diff --cached --name-only --diff-filter=ACM -- '*.ts' '*.tsx' '*.js' '*.mjs')
+[ -z "$files" ] || echo "$files" | xargs npx eslint --no-warn-ignored