feat(cli): unify scaffolding under crewai create <resource> (#6821)

* feat(cli): add canonical `crewai create tool` command

Unify tool scaffolding under the create verb and deprecate
`crewai tool create` with a yellow warning while keeping backward
compatibility.

* feat(cli): add canonical `crewai create skill` command

Unify skill scaffolding under the create verb and deprecate
`crewai skill create` with a yellow warning while keeping backward
compatibility.

* feat(cli): add canonical `crewai create template` command

Unify template scaffolding under the create verb and deprecate
`crewai template add` with a yellow warning while keeping backward
compatibility.

* docs: document unified `crewai create` scaffolding commands

Document canonical create forms for tool, skill, and template projects,
note deprecated aliases, and update skills and agents-md guides.

* feat(cli): extend create picker and DMN guidance for all types

Show tool, skill, and template in the interactive create picker and
list every supported type in the CREWAI_DMN usage error.

* fix(cli): allow create tool/skill/template in CREWAI_DMN mode

Only set skip_provider in DMN mode for crew creation, since tool,
skill, and template paths reject that flag as a crew-only option.

* test(cli): patch TemplateCommand at cli lookup site in DMN test

create() resolves TemplateCommand from crewai_cli.cli, not from
remote_template.main directly.

lib/cli/tests/test_cli.py

@@ -228,6 +228,7 @@ def test_create_requires_type_in_dmn_mode(runner):
 
     assert result.exit_code == 2
     assert "TYPE is required when CREWAI_DMN is set" in result.output
+    assert "crew, flow, tool, skill, template" in result.output
 
 
 def test_create_requires_name_in_dmn_mode(runner):