docs: add license, CI, fix content quality, document rcd provider (#38)

- Add 0BSD LICENSE (matches gogrlx/grlx)
- Add GitHub Actions CI workflow (build + eslint)
- Fix eslint config: add ignores for .astro/dist, add typescript parser deps
- Update README: replace npm boilerplate with bun commands, add badges
- Document rc.d (BSD) service provider alongside systemd
- Update service ingredient to reference provider interface instead of claiming systemd-only
- Fix frontmatter: desc -> description in groups.md and user.md
- Close unclosed :::note directive in ingredients overview
- Fix typo in ingredients overview ('Check them out the list' -> 'Check out the list')
- Update astro 5.17.3 -> 5.18.0

.github/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      - run: bun install --frozen-lockfile
+
+      - run: bun run build
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      - run: bun install --frozen-lockfile
+
+      - run: bunx eslint .