Add ssl_verify config option to fix certificate errors

Raw OpenSSL sockets don't find the system CA bundle the same way Net::HTTP
does. ssl_verify (default: true) is now a config setting that applies to
both HTTP REST calls and WebSocket connections. Set via `portainer-cli configure`.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/portainer_cli/client.rb

@@ -60,7 +60,7 @@ module PortainerCli
       http = Net::HTTP.new(uri.host, uri.port)
       if uri.scheme == 'https'
         http.use_ssl     = true
-        http.verify_mode = OpenSSL::SSL::VERIFY_PEER
+        http.verify_mode = @config.ssl_verify ? OpenSSL::SSL::VERIFY_PEER : OpenSSL::SSL::VERIFY_NONE
       end
       http.open_timeout = 10
       http.read_timeout = 30