fix(deps): regenerates lockfile for pinned happy-dom, adds lockfile sync hook

- pnpm-lock.yaml specifier was ^20.8.9, package.json was pinned to
  20.8.9 — CI frozen-lockfile install failed on the mismatch
- adds lockfile-sync pre-commit hook that runs pnpm install
  --frozen-lockfile when package.json or pnpm-lock.yaml changes

Author: wgordon17

pnpm-lock.yaml

@@ -13,6 +13,15 @@ hooks = [
 [[repos]]
 repo = "local"
 
+[[repos.hooks]]
+id = "lockfile-sync"
+name = "Lockfile in sync with package.json"
+language = "system"
+entry = "pnpm install --frozen-lockfile"
+pass_filenames = false
+files = "(package\\.json|pnpm-lock\\.yaml)$"
+priority = 0
+
 [[repos.hooks]]
 id = "typecheck"
 name = "TypeScript typecheck"