Fix: Handle whitespace-only tags from Proxmox API to prevent false Terraform diffs

[aleskxyz]

Problem

Proxmox API sometimes (when you set tag for VMs/containers and then remote it) returns "tags": " " (a single space character) for VMs/containers that have no tags set. This causes false diffs in Terraform when the provider compares the state with the configuration:

~ resource "proxmox_vm_qemu" "vm" {
tags = " " -> null
}

The issue occurs because the SDK's mapToSDK function was treating the whitespace string as a valid tag, creating a Tags slice with a single tag containing a space character.

Solution

Updated Tags.mapToSDK() in proxmox/type__tag.go to:

• Trim whitespace from the input string before processing
• Filter out empty tags after splitting by semicolon
• Return empty Tags{} when the input is only whitespace

This ensures that when Proxmox returns "tags": " ", it's correctly interpreted as "no tags" rather than "one tag with a space".

Test

Before:

./proxmox-api-go get guest config 247 -i | jq '.tags'
[
  " "
]

After:

./proxmox-api-go get guest config 247 -i | jq '.tags'
[]

[Tinyblargon]

@aleskxyz Thank you for this contribution :)