chore: rework plugin readmes, json changelogs and standalone repo setup

plugins/snippets/CONTRIBUTING.md

@@ -0,0 +1,27 @@
+# Contributing to Snippets
+
+## Development
+
+```bash
+npm run build      # build into dist/
+npm run test       # run this plugin's tests
+npm run typecheck  # type-check this plugin
+npm run validate   # check manifest.json
+npm run format     # format the code with Prettier
+```
+
+## Settings
+
+### User
+
+- **Collapse folders by default:** start each folder closed in the Snippets panel
+- **Show commands:** show the first line of each command under its name
+- **Confirm before running:** ask before a command snippet runs in a terminal
+
+## Permissions
+
+- `snippets.view`: see your own and shared snippets. Admins and users have it by default.
+- `snippets.create`: create snippets, notes and folders. Admins and users have it by default.
+- `snippets.edit`: change snippets and folders. Admins and users have it by default.
+- `snippets.delete`: delete snippets and folders. Admins and users have it by default.
+- `snippets.share`: share snippets and folders. Admins and users have it by default.