Migrate pre-commit hooks from pre-commit to prek

Replace the Python-based pre-commit framework with prek (Rust) for
faster hook execution. Convert .pre-commit-config.yaml to prek.toml,
remove pre-commit from dev dependencies, and apply ruff auto-fixes
(UP037: remove unnecessary string quotes in type annotations).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prek.toml

@@ -0,0 +1,47 @@
+# Configuration file for `prek`, a git hook framework written in Rust.
+# See https://prek.j178.dev for more information.
+#:schema https://www.schemastore.org/prek.json
+
+[[repos]]
+repo = "https://github.com/astral-sh/ruff-pre-commit"
+rev = "v0.15.0"
+hooks = [
+  {
+    id = "ruff",
+    args = ["--fix"],
+    files = "^backend/"
+  },
+  {
+    id = "ruff-format",
+    files = "^backend/"
+  }
+]
+
+[[repos]]
+repo = "local"
+hooks = [
+  {
+    id = "oxlint",
+    name = "oxlint",
+    entry = "npx oxlint -c frontend/.oxlintrc.json",
+    language = "system",
+    files = '^frontend/src/.*\.(ts|tsx)$',
+    pass_filenames = true
+  },
+  {
+    id = "oxfmt",
+    name = "oxfmt",
+    entry = "npx oxfmt --check --config frontend/.oxfmtrc.json",
+    language = "system",
+    files = '^frontend/src/.*\.(ts|tsx)$',
+    pass_filenames = true
+  },
+  {
+    id = "tsc",
+    name = "tsc",
+    entry = "bash -c 'cd frontend && npx tsc -b'",
+    language = "system",
+    files = '^frontend/src/.*\.(ts|tsx)$',
+    pass_filenames = false
+  }
+]