docs: clarify proxmox fresh install state and potential breaking changes

BOOTSTRAP.md

@@ -23,10 +23,19 @@ We use `sops-nix` to manage secrets, adhering to a strict separation between Pro
 3. **Update Configuration:**
    Open both `.txt` files and copy their **Public Keys** (the strings starting with `age1...`). Open `.sops.yaml` in the root of this repository and replace the `# TODO` placeholders with your newly generated public keys. Commit and push this change.
 
-## 2. Proxmox Hypervisor Authentication
+## 2. Proxmox Hypervisor Authentication & State
 
 The CI/CD pipeline needs restricted API access to Proxmox to provision Virtual Machines. 
 
+### Fresh Install vs. Existing Install
+> [!WARNING]
+> This repository assumes a standard, fresh installation of Proxmox VE. 
+> 
+> **If you are NOT starting from a fresh install, be aware of these potential breaking changes:**
+> * **VM ID Conflicts:** Terraform automatically assigns VM IDs. If you have existing VMs, Terraform might fail to provision or (if misconfigured) attempt to overwrite them. Check your Terraform variables to ensure the ID range (e.g., 8000+) does not conflict.
+> * **Storage Pools:** The automation assumes the default Proxmox storage pools (`local` for snippets/ISOs, and `local-lvm` or `local-zfs` for VM disks). If you renamed your pools, you must update the Terraform configuration.
+> * **Network Bridges:** It assumes `vmbr0` is available for VM networking.
+
 **Prerequisites:** Install `terraform` ([Terraform installation](https://developer.hashicorp.com/terraform/downloads)).
 
 1. Ensure you have network access to your Proxmox host (e.g., via Tailscale).