fix: match LXC template to host architecture

README.md

@@ -306,7 +306,7 @@ The installer will prompt for container settings (container ID, hostname, RAM,
 disk, bridge, etc.), whether to install the host-side CH341 udev rule, and
 whether to download the optional openHop Console WebUI. It will then:
 
-1. Download a Debian 13 LXC template.
+1. Download a Debian 13 LXC template matching the Proxmox host architecture.
 2. Create a privileged container with USB passthrough.
 3. Install the host-side CH341 udev rule only when selected. This is not needed
    for openHop Modem TCP or USB connections and defaults to No.

scripts/proxmox-install.sh

@@ -84,6 +84,13 @@ fi
 
 msg_ok "Running on Proxmox host as root"
 
+CT_ARCH=$(dpkg --print-architecture)
+if [[ ! "$CT_ARCH" =~ ^(amd64|arm64)$ ]]; then
+    msg_error "Unsupported Proxmox host architecture: ${CT_ARCH}"
+    exit 1
+fi
+msg_ok "Detected Proxmox host architecture: ${CT_ARCH}"
+
 # Default to the next available container ID, but allow the user to choose.
 DEFAULT_CTID=$(pvesh get /cluster/nextid)
 
@@ -154,10 +161,14 @@ read -p "  Proceed? [Y/n]: " -r
 echo ""
 msg_info "Downloading Debian 13 template..."
 TEMPLATE_FILE=$(pveam available -section system 2>/dev/null \
-    | awk -v template="$CT_TEMPLATE" '$2 ~ template {print $2}' \
+    | awk -v template="$CT_TEMPLATE" -v arch="$CT_ARCH" \
+        '$2 ~ ("^" template "_") && $2 ~ ("_" arch "\\.tar\\.") {print $2}' \
     | sort -V \
     | tail -1)
-[ -z "$TEMPLATE_FILE" ] && { msg_error "Template not found. Run: pveam update"; exit 1; }
+[ -z "$TEMPLATE_FILE" ] && {
+    msg_error "Debian 13 template for ${CT_ARCH} not found. Run: pveam update"
+    exit 1
+}
 
 pveam list "$CT_TEMPLATE_STORAGE" 2>/dev/null | grep -q "$TEMPLATE_FILE" || \
     pveam download "$CT_TEMPLATE_STORAGE" "$TEMPLATE_FILE"

tests/test_proxmox_installer.py

@@ -15,6 +15,15 @@ def test_proxmox_installer_uses_debian_13() -> None:
     assert "Debian 12" not in script
 
 
+def test_template_selection_matches_the_proxmox_host_architecture() -> None:
+    script = INSTALLER.read_text()
+
+    assert "CT_ARCH=$(dpkg --print-architecture)" in script
+    assert '[[ ! "$CT_ARCH" =~ ^(amd64|arm64)$ ]]' in script
+    assert '-v arch="$CT_ARCH"' in script
+    assert '$2 ~ ("_" arch "\\\\.tar\\\\.")' in script
+
+
 def test_installer_allows_explicit_repository_and_branch_for_fork_testing() -> None:
     script = INSTALLER.read_text()