chore: project setup and tooling cleanup (#26)

* add project setup

* add tools to eslint

* remove contributing.md

* update claude md

* chore: simplify CI to single Node.js version (22)

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

* use node 20

* adjust formatting

* fix linting

* format

* fix layout

* fix: align CI node version to .nvmrc (22), remove redundant gotcha

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

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: arkon <arkon.85@hotmail.com>

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+
+jobs:
+  ci:
+    name: Typecheck & Lint
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Type check
+        run: npm run typecheck
+
+      - name: Lint
+        run: npm run lint
+
+      - name: Format check
+        run: npm run format:check
+
+# Note: The test suite is intentionally excluded from CI.
+# Tests spawn real tmux sessions and require a full system environment.
+# Run tests locally with: npx vitest run test/<file>.test.ts