chore: add npm trusted publishing workflow

Author: ya-nsh

.github/workflows/publish-npm.yml

@@ -0,0 +1,51 @@
+name: Publish npm
+
+on:
+  workflow_dispatch:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: read
+
+concurrency:
+  group: publish-npm
+  cancel-in-progress: false
+
+jobs:
+  publish:
+    name: Publish tokenleak to npm
+    if: github.repository == 'ya-nsh/tokenleak' && (github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/v'))
+    runs-on: ubuntu-latest
+    environment: npm-publish
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "24"
+          registry-url: "https://registry.npmjs.org"
+
+      - name: Set up Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: "1.3.10"
+
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+
+      - name: Run checks
+        run: bun run check
+
+      - name: Prepare npm package
+        run: bun run prepublish
+
+      - name: Publish to npm
+        working-directory: dist
+        run: npm publish

CONTRIBUTING.md

@@ -61,6 +61,38 @@ bun run format
 
 5. Never commit directly to `main`.
 
+## Release Publishing
+
+Tokenleak publishes to npm from GitHub Actions with npm Trusted Publishing. The publish workflow does not store an npm token and does not run for pull requests.
+
+Configure the package once from an npm account with publish access:
+
+```bash
+npm trust github tokenleak --repo ya-nsh/tokenleak --file publish-npm.yml --env npm-publish
+```
+
+Use these trusted publisher fields if configuring in npmjs.com instead:
+
+- Provider: GitHub Actions
+- Organization or user: `ya-nsh`
+- Repository: `tokenleak`
+- Workflow file: `publish-npm.yml`
+- Environment: `npm-publish`
+- Allowed action: `npm publish`
+
+After a release PR is merged and the version is ready, publish with one of:
+
+```bash
+# Manual release from the default branch
+gh workflow run publish-npm.yml --ref main
+
+# Tag-triggered release
+git tag v<version>
+git push origin v<version>
+```
+
+Only users with write access to the repository can manually trigger the workflow or push release tags. Forks and pull requests cannot publish because the workflow has no `pull_request` trigger, and the publish job is restricted to `ya-nsh/tokenleak` on `main` or `v*` tags.
+
 ## Code Style
 
 - **Strict TypeScript**: No `any` types. Use `unknown` and narrow properly.