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

plugins/tmux-monitor/CONTRIBUTING.md

@@ -0,0 +1,22 @@
+# Contributing to Tmux Monitor
+
+## 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
+
+### Host
+
+- **Enable Tmux Monitor:** show this host in the monitor and add its tmux actions to the sidebar
+- **Enable tmux mouse support:** turn on mouse support when attaching or creating a session
+
+## Permissions
+
+- `tmux-monitor.use`: browse and control tmux sessions on hosts with the monitor on. Admins and users have it by default.