Align project structure with silverbullet-plug-template

- Rename deno.jsonc to deno.json and update build tasks
- Add PLUG.md for SB v2 installation
- Update .gitignore to include .plug.js files
- Update README.md with new installation instructions
- Simplify GitHub workflow

.github/workflows/publish.yml

@@ -19,12 +19,6 @@ jobs:
           deno-version: v2.x
 
 
-      - name: Install SilverBullet CLI
-        run: |
-          # Install the CLI directly from the main source entry point
-          deno install --global -f -A --name silverbullet https://raw.githubusercontent.com/silverbulletmd/silverbullet/main/source/main.ts
-          echo "$HOME/.deno/bin" >> $GITHUB_PATH
-
       - name: Build Plug
         run: deno task build