feat: add incus auto-client certificate trust

- add fact to export vault public cert from agents
- add fact to export list of trusted incus client certs
- add method for incus clients to export their client cert to be trusted

modules/libs/lib/facter/vault_cert_content.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+# lib/facter/vault_cert_content.rb
+
+Facter.add(:vault_cert_content) do
+  confine kernel: 'Linux'
+  setcode do
+    cert_path = '/etc/pki/tls/vault/certificate.crt'
+    File.read(cert_path) if File.exist?(cert_path) && File.readable?(cert_path)
+  end
+end

modules/libs/lib/facter/vault_cert_fingerprint.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# lib/facter/vault_cert_fingerprint.rb
+
+Facter.add(:vault_cert_fingerprint) do
+  confine kernel: 'Linux'
+  setcode do
+    require 'openssl'
+    require 'digest'
+
+    cert_path = '/etc/pki/tls/vault/certificate.crt'
+    if File.exist?(cert_path) && File.readable?(cert_path)
+      begin
+        cert_content = File.read(cert_path)
+        cert = OpenSSL::X509::Certificate.new(cert_content)
+        # Calculate SHA256 fingerprint like incus does
+        Digest::SHA256.hexdigest(cert.to_der)
+      rescue StandardError
+        nil
+      end
+    end
+  end
+end