chore: update project configuration and add linting/formatting tools

.changeset/README.md

@@ -0,0 +1,9 @@
+# Changesets
+
+This directory contains changesets — short Markdown files that describe changes to packages in this repo.
+
+When you run `pnpm changeset`, a new file is created here. Commit it with your PR.
+
+When a PR is merged to `main`, the `release.yml` workflow consumes these files, bumps the relevant `package.json` versions, and opens a **Version Packages** PR. After that PR is merged, the workflow creates git tags and publishes the affected codemods.
+
+See [Changesets docs](https://github.com/changesets/changesets) for more detail.

.changeset/config.json

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+{
+  "$schema": "https://unpkg.com/@changesets/config@3.1.1/schema.json",
+  "changelog": "@changesets/cli/changelog",
+  "commit": false,
+  "fixed": [],
+  "linked": [],
+  "access": "public",
+  "baseBranch": "main",
+  "updateInternalDependencies": "patch",
+  "ignore": [],
+  "privatePackages": {
+    "version": true,
+    "tag": true
+  }
+}

.github/workflows/ci.yaml

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+name: CI
+
+on:
+  pull_request:
+    branches:
+      - main
+
+permissions:
+  contents: read
+
+jobs:
+  ci:
+    name: CI
+    runs-on: ubuntu-slim
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: pnpm/action-setup@v4
+
+      - run: pnpm install --frozen-lockfile
+
+      - run: pnpm run format:check
+
+      - run: pnpm run lint
+
+      - run: pnpm run check-types
+
+      - name: Run tests for changed codemods
+        shell: bash
+        run: |
+          changed_paths=$(git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.sha }})
+
+          if echo "$changed_paths" | grep -qE '^(package\.json|pnpm-lock\.yaml|pnpm-workspace\.yaml|\.github/workflows/ci\.yml)$'; then
+            pnpm test
+            exit 0
+          fi
+
+          filters=$(
+            echo "$changed_paths" \
+              | grep '^codemods/' \
+              | cut -d/ -f1-3 \
+              | sort -u \
+              | sed 's|^|--filter ./|'
+          )
+
+          if [ -z "$filters" ]; then
+            echo "No codemod packages affected; skipping tests."
+            exit 0
+          fi
+
+          # shellcheck disable=SC2086
+          pnpm $filters test