ci: add format, lint, and typecheck quality checks

.github/workflows/quality-checks.yml

@@ -0,0 +1,86 @@
+name: Quality checks
+
+on:
+  pull_request:
+  push:
+
+jobs:
+  format:
+    name: Format check
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+      - name: Setup node
+        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
+        with:
+          node-version-file: '.node-version'
+          cache: 'npm'
+      - name: Install dependencies
+        run: npm ci
+      - name: Check formatting
+        run: npm run fmt:check
+
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+      - name: Setup node
+        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
+        with:
+          node-version-file: '.node-version'
+          cache: 'npm'
+      - name: Install dependencies
+        run: npm ci
+      - name: Run ESLint
+        run: npm run lint
+
+  typecheck:
+    name: Typecheck
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+      - name: Setup node
+        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
+        with:
+          node-version-file: '.node-version'
+          cache: 'npm'
+      - name: Install dependencies
+        run: npm ci
+      - name: Run TypeScript typecheck
+        run: npm run typecheck -- --pretty false
+
+  knip:
+    name: Knip
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+      - name: Setup node
+        uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
+        with:
+          node-version-file: '.node-version'
+          cache: 'npm'
+      - name: Install dependencies
+        run: npm ci --ignore-scripts
+      - name: Run Knip
+        run: npm run knip

CONTRIBUTING.md

@@ -37,6 +37,13 @@ It is not always possible to phrase every change in such a manner, but it is des
 
 Also, we use [ESLint](https://eslint.org/) for clean and stylistically consistent code syntax, so make sure your pull request follow it.
 
+**Pull requests are not merged unless all quality checks are passing.** At minimum, `format`, `lint`, `typecheck`, and `knip` must all be green before a pull request can be merged. Run these locally before opening or updating a pull request:
+
+- `npm run fmt:check`
+- `npm run lint`
+- `npm run typecheck`
+- `npm run knip`
+
 **For any query or design discussion, join our [Matrix room](https://matrix.to/#/#sable:sable.moe).**
 
 ## Helpful links