Fix 5 pre-release bugs

- Help text showed wrong config path (~/.portainer-cli vs ~/.config/portainer-cli)
- --port without colon (e.g. --port 8080) crashed with nil/tcp key; now errors clearly
- --cmd used naive split(' ') breaking quoted args; switched to Shellwords.split
- --env without '=' (e.g. --env FOO) silently passed empty value; now errors clearly
- SSL/connection errors surfaced as raw exception; now caught with actionable message

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

lib/portainer_cli/commands/create.rb

@@ -2,6 +2,7 @@
 
 require_relative 'base'
 require 'optparse'
+require 'shellwords'
 
 module PortainerCli
   module Commands
@@ -55,6 +56,7 @@ module PortainerCli
         end
 
         env_vars = opts[:env].map do |pair|
+          error("Invalid --env '#{pair}': expected KEY=VALUE") unless pair.include?('=')
           k, v = pair.split('=', 2)
           { 'name' => k, 'value' => v.to_s }
         end
@@ -90,7 +92,11 @@ module PortainerCli
         port_bindings = {}
         exposed_ports = {}
         opts[:ports].each do |mapping|
-          host_port, cont_port = mapping.split(':', 2)
+          parts = mapping.split(':', 2)
+          error("Invalid --port '#{mapping}': expected HOST:CONTAINER (e.g. 8080:80)") unless parts.size == 2
+          host_port, cont_port = parts
+          error("Invalid --port '#{mapping}': missing host port")      if host_port.empty?
+          error("Invalid --port '#{mapping}': missing container port") if cont_port.empty?
           cont_key = "#{cont_port}/tcp"
           exposed_ports[cont_key] = {}
           port_bindings[cont_key] = [{ 'HostPort' => host_port }]
@@ -102,7 +108,7 @@ module PortainerCli
           'ExposedPorts' => exposed_ports,
           'HostConfig'   => { 'PortBindings' => port_bindings }
         }
-        body['Cmd'] = opts[:cmd].split(' ') if opts[:cmd]
+        body['Cmd'] = Shellwords.split(opts[:cmd]) if opts[:cmd]
 
         query = opts[:name] ? "?name=#{URI.encode_www_form_component(opts[:name])}" : ''
         result = @client.post("/api/endpoints/#{opts[:endpoint]}/docker/containers/create#{query}", body)