feat: Added multiple SSH Key uploads

readme.md

@@ -68,9 +68,9 @@ architecture-beta
 .
 ├── infra/                    # OpenTofu (Terraform-compatible) config — provisions the 3 servers, network, firewalls, volumes
 │   ├── main.tf                # root module: wires network + dev/prod/vpn modules together
-│   ├── variables.tf           # shared inputs (sizes, locations, IP ranges, SSH key name)
+│   ├── variables.tf           # shared inputs (sizes, locations, IP ranges, SSH key names)
 │   ├── outputs.tf             # pass-through outputs from each host module
-│   ├── ssh.tf                 # looks up the SSH key already uploaded to Hetzner Cloud
+│   ├── ssh.tf                 # looks up each SSH key already uploaded to Hetzner Cloud
 │   ├── versions.tf            # provider requirements
 │   ├── terraform.tfvars.example
 │   ├── scripts/
@@ -98,7 +98,7 @@ Each of `services/dev`, `services/prod`, `services/vpn` follows the same convent
 ## Prerequisites
 
 - A [Hetzner Cloud](https://console.hetzner.cloud/) project and API token
-- An SSH key uploaded to that project (Console → Security → SSH Keys), and the matching private key available locally (OpenTofu uses it once per server to run the post-install bootstrap — see below)
+- One or more SSH keys uploaded to that project (Console → Security → SSH Keys) - all are installed on every server - plus the private key matching one of them available locally (OpenTofu uses it once per server to run the post-install bootstrap — see below)
 - [OpenTofu](https://opentofu.org/docs/intro/install/) `>= 1.6.0`
 - DNS records for the domains in [Service inventory](#service-inventory) pointed at the relevant server's public IP
 
@@ -110,7 +110,7 @@ Docker + the Compose plugin no longer need installing by hand — the bootstrap
 cd infra
 export HCLOUD_TOKEN=your-hetzner-api-token   # never commit this
 cp terraform.tfvars.example terraform.tfvars
-$EDITOR terraform.tfvars                     # set ssh_key_name and ssh_private_key_path at minimum
+$EDITOR terraform.tfvars                     # set ssh_key_names and ssh_private_key_path at minimum
 
 tofu init
 tofu plan
@@ -131,7 +131,7 @@ Useful outputs: `tofu output dev_ipv4`, `tofu output prod_ipv4`, `tofu output vp
 Immediately after each `hcloud_server` is created, OpenTofu uploads and runs [`infra/scripts/bootstrap.sh.tftpl`](infra/scripts/bootstrap.sh.tftpl) over SSH as `root` (`connection` + `file`/`remote-exec` provisioners in each `modules/<host>/main.tf`). It:
 
 - installs Docker Engine + the Compose plugin
-- creates a non-root sudo user (`var.deploy_user`, default `deploy`) with the same SSH key as root, in the `sudo` and `docker` groups
+- creates a non-root sudo user (`var.deploy_user`, default `deploy`) with the same SSH keys as root, in the `sudo` and `docker` groups
 - hardens `sshd`: password authentication off, root login restricted to key-only (`PermitRootLogin prohibit-password`)
 - installs and enables `unattended-upgrades` for automatic security patches