chore: Setup automated publishing with changesets (#2)

- Add changesets CLI for version management
- Configure GitHub Actions workflow for automated publishing
- Publish to npm (primary) and GitHub Packages (secondary)
- Add npm scripts: changeset, version, release
- Configure publishConfig for public access

Workflow:
- Runs on push to main with changesets
- Creates "Version Packages" PR automatically
- Publishes to npm first (fail-fast)
- Then publishes to GitHub Packages if npm succeeds

Author: lxcid

.changeset/README.md

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+# Changesets
+
+Hello! 👋
+
+This folder contains "changeset" files - each one describes a change to the package.
+
+## Quick Start
+
+### Adding a changeset
+
+When you make a change that should trigger a release:
+
+```bash
+npm run changeset
+```
+
+Follow the prompts:
+1. **Select change type**: patch, minor, or major
+2. **Write a summary**: Describe what changed
+
+### What happens next?
+
+1. Commit the changeset file
+2. Push to `main` branch
+3. GitHub Action creates a "Version Packages" PR
+4. Merge that PR to publish
+
+## Change Types
+
+- **patch** (1.0.0 → 1.0.1): Bug fixes
+- **minor** (1.0.0 → 1.1.0): New features
+- **major** (1.0.0 → 2.0.0): Breaking changes
+
+## Example
+
+```bash
+# Make your changes
+git add .
+git commit -m "fix: timezone validation"
+
+# Add changeset
+npm run changeset
+# → Select: patch
+# → Summary: "Fix timezone offset range to support UTC-12 to UTC+14"
+
+# Commit and push
+git add .changeset
+git commit -m "chore: add changeset"
+git push
+```
+
+## Learn More
+
+- [Changesets Documentation](https://github.com/changesets/changesets)
+- See `PUBLISHING.md` for full workflow details

.changeset/config.json

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+{
+  "$schema": "https://unpkg.com/@changesets/config@3.1.2/schema.json",
+  "changelog": "@changesets/cli/changelog",
+  "commit": false,
+  "fixed": [],
+  "linked": [],
+  "access": "public",
+  "baseBranch": "main",
+  "updateInternalDependencies": "patch",
+  "ignore": []
+}

.github/workflows/publish.yml

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+name: Publish Package
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      packages: write
+      pull-requests: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22.x'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test
+
+      - name: Build
+        run: npm run build
+
+      # Configure npm registry for publishing
+      - name: Setup Node.js for npm
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22.x'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Create Release Pull Request or Publish to npm
+        id: changesets
+        uses: changesets/action@v1
+        with:
+          publish: npm run release
+          title: 'chore: version packages'
+          commit: 'chore: version packages'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+
+      # Only publish to GitHub Packages if npm publish succeeded
+      - name: Setup Node.js for GitHub Packages
+        if: steps.changesets.outputs.published == 'true'
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22.x'
+          registry-url: 'https://npm.pkg.github.com'
+          scope: '@taskade'
+
+      - name: Publish to GitHub Packages
+        if: steps.changesets.outputs.published == 'true'
+        run: npm publish
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}