feat(agent): lint and format staged changes on commit

.githooks/pre-commit

@@ -0,0 +1,12 @@
+#!/bin/sh
+root=$(git rev-parse --show-toplevel 2>/dev/null) || exit 1
+if [ ! -x "$root/node_modules/.bin/lint-staged" ]; then
+  echo "pre-commit: worktree preparation is incomplete (lint-staged is missing)" >&2
+  echo "pre-commit: run pnpm install before committing" >&2
+  exit 1
+fi
+# The binary directly, not `pnpm lint-staged`: pnpm runs a dependency-status
+# check first and will try to purge node_modules when the lockfile moved, which
+# aborts without a TTY — the commit then fails with a pnpm error that says
+# nothing about linting. The guard above already established this path exists.
+exec "$root/node_modules/.bin/lint-staged"

lint-staged.config.js

@@ -0,0 +1,29 @@
+const dprint = "dprint fmt --config dprint.jsonc"
+
+/**
+ * Staged files are linted as well as formatted, so a lint error is caught at the
+ * commit that introduced it rather than at the push gate or in CI.
+ *
+ * Lint and format share one array rather than two glob entries: lint-staged runs
+ * separate entries concurrently, and both of these rewrite the file. The globs
+ * below are disjoint for the same reason.
+ *
+ * `oxlint` here is the fast, non-type-aware pass — what can run per file in the
+ * time a commit should take. The full `--type-aware` lint and the format check
+ * still run in the ship gate and in CI, so this narrows the feedback loop rather
+ * than replacing them.
+ *
+ * `--no-error-on-unmatched-pattern` is required, not cosmetic: `.oxlintrc.json`
+ * ignores whole categories of file — `.js`, `.jsx`, `.d.ts` and `repos/**` among
+ * them — and without it oxlint exits non-zero on "No files found to lint", so
+ * staging only an ignored file would block the commit for no reason.
+ *
+ * @type {import('lint-staged').Configuration}
+ */
+export default {
+  "*.{ts,tsx,mts,cts}": [
+    "oxlint --quiet --fix --no-error-on-unmatched-pattern",
+    dprint
+  ],
+  "*.{js,jsx,mjs,cjs,json,jsonc,md,toml,css,scss,sass,less,html,yml,yaml}": dprint
+}

package.json

@@ -61,6 +61,7 @@
     "effect-app": "workspace:*",
     "eslint": "^10.4.1",
     "json5": "^2.2.3",
+    "lint-staged": "^17.3.0",
     "madge": "^8.0.0",
     "npm-check-updates": "^22.2.1",
     "oxlint": "^1.67.0",