Add OpenAPI generation command

[rtcoder]

Changes

• Add ./shift openapi to generate an OpenAPI 3.0 JSON document from registered module routes.
• Support ./shift openapi --output=docs/openapi.json for writing the generated document to a file.
• Add ./shift openapi --validate and include OpenAPI validation in ./shift qa.
• Add ./shift openapi --live to start a local Swagger-like documentation server backed by generated openapi.json.
• Support live server binding options with --host= and --port=, defaulting to http://127.0.0.1:8088.
• Add OpenAPI documentation attributes: Summary, Description, Tag, Response, Deprecated, Security, and Schema.
• Generate paths, methods, operation ids, tags, summaries, descriptions, path parameters, query parameters, request bodies, DTO schemas, response statuses, response headers, security metadata, deprecation metadata, formats, enums, nullable fields, and required fields from code.
• Improve the live viewer with endpoint search, tag filtering, dark mode, operation counts, security display, and JSON download.
• Add api:docs as an alias for the OpenAPI command.
• Document the command and attributes in README, docs/index.html, and REFACTORING.md.
• Add tests for command discovery, route attribute generation, OpenAPI attributes, DTO schemas, output files, module route generation, validation, live page rendering, and live option help.

Verification

• composer test
• ./shift lint
• ./shift qa
• ./shift openapi
• ./shift openapi --validate
• ./shift openapi --output=
• ./shift openapi --live --port=8099 with HTTP checks for / and /openapi.json
• ./shift help openapi
• Documentation anchor check for all in-page navigation links

Release

• Version label: v0.22.0