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

plugins/proxmox/CONTRIBUTING.md

@@ -0,0 +1,25 @@
+# Contributing to Proxmox
+
+## 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 Proxmox:** mark this host as a Proxmox node so its guests can be imported
+- **Default Auth Type and Default Credential:** the login given to imported guests
+- **Windows / RDP detection and Docker detection:** name patterns that switch guests to RDP or turn on Docker
+- **Preferred IP ranges:** IP prefixes to prefer, in order
+- **Auto sync guests and Sync interval (minutes):** check the node for changes on a schedule, at least every 5 minutes
+- **Mark missing guests:** tag guests that disappear as `proxmox-missing` instead of deleting them
+- **Enable Proxmox Stats:** show the Proxmox Stats tab for this host
+- **Poll interval (seconds):** how often stats refresh, at least 15 seconds
+- **Node name override:** use this node name instead of the detected one