chore: prepare for v2.0.0 (#405)

## Summary

This PR prepares `supabase/setup-cli` for `v2.0.0`.

The main goal of this release is to simplify the action and modernize
the repo/tooling around a Bun-based implementation, while tightening
workflows, tests, and documentation.

## What Changed

### Action runtime
- switched the action from a Node/compiled `dist` runtime to a Bun-based
composite action
- removed the checked-in `dist/` output entirely
- simplified the action source down to a single runtime file in
`src/main.ts`
- kept the public action interface the same:
  - `with.version`
  - `outputs.version`

### Tooling
- switched package management and local tooling from npm to Bun
- removed Rollup and the build step
- replaced Jest with Bun’s native test runner
- replaced Prettier with `oxfmt`
- replaced ESLint with `oxlint`
- enabled type-aware/type-check linting with `oxlint-tsgolint`
- simplified TypeScript config to a single `tsconfig.json` extending
`@tsconfig/bun`

### Tests
- moved tests next to the runtime source
- rewrote tests to focus on meaningful user-facing action behavior
- added coverage for:
  - default entrypoint execution
  - latest version installs
  - legacy version installs
  - modern pinned version installs
  - failure when the installed CLI cannot report a version
- action code coverage is now `100%`

### Workflows
- renamed workflow files for clarity:
  - `test.yml` -> `ci.yml`
  - `start.yml` -> `e2e.yml`
- updated workflow/job naming so required checks are clean and stable:
  - `CI`
  - `E2E`
  - `CodeQL`
  - `Licensed`
- added aggregate PR-facing checks so branch protection does not need
matrix legs
- made CI and E2E skip heavy jobs on draft PRs
- made E2E run automatically on ready PRs and new commits
- simplified CodeQL config by removing the separate config file
- updated action pins to current releases using commit SHAs
- refined Dependabot for Bun-era updates and non-major auto-merge

### Docs
- refreshed `README.md` and `docs/index.md` for the new v2 behavior
- updated examples to use `@v2`
- added a practical example for exporting local Supabase env vars after
`supabase start`
- removed stale references to old local/dev flows

## Breaking / Notable Changes

- the action now runs as a Bun-based composite action instead of a
prebuilt JavaScript action
- no checked-in `dist/` artifacts anymore
- self-hosted runners now need the prerequisites expected by the
composite action path:
  - `bash`
- network access to install Bun/dependencies and download the Supabase
CLI

## Validation

Verified locally with:
- `bun run format:check`
- `bun run lint`
- `bun test`
- `bun run ci`

Also updated workflows and branch-protection-friendly check names so PR
validation is cleaner going forward.

## Follow-up

After merge, branch protection should require only:
- `CI`
- `E2E`
- `CodeQL`
- `Licensed`

---------

Co-authored-by: licensed-ci <licensed-ci@users.noreply.github.com>

.github/workflows/licensed.yml

@@ -6,39 +6,54 @@ name: Licensed
 
 on:
   pull_request:
+    paths:
+      - .github/workflows/licensed.yml
+      - .licensed.yml
+      - .licenses/**
+      - bun.lock
+      - package.json
   push:
     branches:
       - main
+    paths:
+      - .github/workflows/licensed.yml
+      - .licensed.yml
+      - .licenses/**
+      - bun.lock
+      - package.json
   workflow_dispatch:
 
-permissions:
-  contents: write
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
-  licensed:
-    name: Check Licenses
+  check-licenses:
+    if: ${{ github.event_name != 'workflow_dispatch' }}
+    name: Licensed
     runs-on: ubuntu-latest
+    timeout-minutes: 15
+    permissions:
+      contents: read
 
     steps:
       - name: Checkout
         id: checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Setup Bun
+        id: setup-bun
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2.2.0
         with:
-          persist-credentials: false
-      - name: Setup Node.js
-        id: setup-node
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version-file: .node-version
-          cache: npm
+          bun-version-file: .bun-version
 
       - name: Install Dependencies
-        id: npm-ci
-        run: npm ci
+        id: bun-install
+        run: bun install --frozen-lockfile
 
       - name: Setup Ruby
         id: setup-ruby
-        uses: ruby/setup-ruby@4dc28cf14d77b0afa6832d9765ac422dbf0dfedd # v1.298.0
+        uses: ruby/setup-ruby@3ff19f5e2baf30647122352b96108b1fbe250c64 # v1.299.0
         with:
           ruby-version: ruby
 
@@ -47,24 +62,61 @@ jobs:
           version: 4.x
           github_token: ${{ secrets.GITHUB_TOKEN }}
 
-      # If this is a workflow_dispatch event, update the cached licenses.
-      - if: ${{ github.event_name == 'workflow_dispatch' }}
-        name: Update Licenses
+      - name: Check Licenses
+        id: check-licenses
+        run: licensed status
+
+  update-licenses:
+    if: ${{ github.event_name == 'workflow_dispatch' }}
+    name: Update Licenses
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout
+        id: checkout
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Setup Bun
+        id: setup-bun
+        uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2.2.0
+        with:
+          bun-version-file: .bun-version
+
+      - name: Install Dependencies
+        id: bun-install
+        run: bun install --frozen-lockfile
+
+      - name: Setup Ruby
+        id: setup-ruby
+        uses: ruby/setup-ruby@3ff19f5e2baf30647122352b96108b1fbe250c64 # v1.299.0
+        with:
+          ruby-version: ruby
+
+      - uses: licensee/setup-licensed@0d52e575b3258417672be0dff2f115d7db8771d8 # v1.3.2
+        with:
+          version: 4.x
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Update License Cache
         id: update-licenses
         run: licensed cache
 
-      # Then, commit the updated licenses to the repository.
-      - if: ${{ github.event_name == 'workflow_dispatch' }}
-        name: Commit Licenses
+      - name: Format License Files
+        id: format-licenses
+        run: bun x oxfmt --write .licensed.yml .licenses
+
+      - name: Commit Licenses
         id: commit-licenses
         run: |
           git config --local user.email "licensed-ci@users.noreply.github.com"
           git config --local user.name "licensed-ci"
-          git add .
+          git add .licenses .licensed.yml
+          if git diff --cached --quiet; then
+            echo "No license cache changes to commit."
+            exit 0
+          fi
           git commit -m "Auto-update license files"
           git push
-
-      # Last, check the status of the cached licenses.
-      - name: Check Licenses
-        id: check-licenses
-        run: licensed status