Migrate build tooling from Vite to tsdown (#46)

## Summary
This PR replaces the Vite build system with tsdown, a more lightweight
and specialized tool for building TypeScript/JavaScript libraries. The
migration simplifies the build configuration and removes unnecessary
build-related CI steps.

## Key Changes
- **Removed Vite configuration**: Deleted `vite.config.js` which defined
library build settings, entry points, and external dependencies
- **Added tsdown configuration**: Created `tsdown.config.js` with
equivalent build settings including ESM format, TypeScript definitions
generation, and publint validation
- **Updated build script**: Changed `package.json` build command from
`vite build` to `tsdown`
- **Removed lint-package CI job**: Eliminated the separate GitHub
Actions workflow step that ran `npm run build` followed by `publint`, as
tsdown now handles publint validation internally
- **Updated dependencies**: Removed `vite` and `vite-plugin-dts` dev
dependencies, added `tsdown` and `publint` as direct dev dependencies

## Notable Details
- The build output configuration remains functionally equivalent (ESM
format, same entry points)
- External dependency handling (`@projectwallace/css-analyzer`) is
preserved in the new configuration
- TypeScript definitions generation is maintained via tsdown's built-in
`dts` option
- Package linting is now integrated into the build process rather than
being a separate CI step

https://claude.ai/code/session_01VzmRVmcLD7znsBCH2V5Hg7

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: bartveneman

.github/dependabot.yml

@@ -3,11 +3,11 @@
 
 version: 2
 updates:
-  - package-ecosystem: "npm"
-    directory: "/"
+  - package-ecosystem: 'npm'
+    directory: '/'
     schedule:
-      interval: "weekly"
-  - package-ecosystem: "github-actions"
-    directory: "/"
+      interval: 'weekly'
+  - package-ecosystem: 'github-actions'
+    directory: '/'
     schedule:
-      interval: "weekly"
+      interval: 'weekly'

.github/workflows/test.yml

@@ -1,7 +1,7 @@
 # This workflow will do a clean install of node dependencies, build the source code and run tests across different versions of node
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
 
-name: Test
+name: Tests
 
 on:
   push:
@@ -10,53 +10,68 @@ on:
     branches: [main]
 
 jobs:
-  lint-js:
-    name: Lint JS
+  test:
+    name: Unit tests
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v6
-      - name: Lint JS
-        run: npx --yes oxlint@latest -D perf
+      - uses: actions/checkout@v6
+      - name: Use Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 22
+      - run: npm ci --ignore-scripts --no-audit --no-fund
+      - run: npm test
+      - name: Upload coverage reports to Codecov
+        uses: codecov/codecov-action@v5.5.2
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          slug: projectwallace/css-code-quality
 
-  lint-package:
-    name: Lint package
+  check:
+    name: Check types
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v6
+      - uses: actions/checkout@v6
       - name: Use Node.js
         uses: actions/setup-node@v6
         with:
-          cache: npm
-      - run: npm install --no-fund --no-audit --ignore-scripts
+          node-version: 22
+      - run: npm ci --ignore-scripts --no-audit --no-fund
+      - run: npm run check
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - name: Use Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 22
+      - run: npm ci --ignore-scripts --no-audit --no-fund
       - run: npm run build
-      - name: Run publint
-        run: npx --yes publint
 
-  check-types:
-    name: Check types
+  lint:
+    name: Lint
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
       - name: Use Node.js
         uses: actions/setup-node@v6
         with:
-          cache: npm
-      - run: npm install --no-fund --no-audit --ignore-scripts
-      - name: Check types
-        run: npm run check
+          node-version: 22
+      - run: npm ci --ignore-scripts --no-audit --no-fund
+      - run: npm run lint
 
-  test:
-    name: Unit tests
+  npm-audit:
+    name: Audit packages
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - name: Checkout code
+        uses: actions/checkout@v6
       - name: Use Node.js
         uses: actions/setup-node@v6
         with:
-          cache: npm
-      - run: npm install --no-fund --no-audit --ignore-scripts
-      - run: npm run build
-      - run: npm test
+          node-version: 22
+      - run: npm audit --audit-level=high

.gitignore

@@ -1,3 +1,4 @@
+coverage
 dist
 node_modules
 .DS_Store

.oxfmtrc.json

@@ -0,0 +1,7 @@
+{
+	"$schema": "./node_modules/oxfmt/configuration_schema.json",
+	"ignorePatterns": [],
+	"useTabs": true,
+	"semi": false,
+	"singleQuote": true
+}