feat(docset): complete the public API #10

Refs #6

Summary

• Reference services: build.xrefService addresses holding {uid} are asked for identities a trial build leaves unresolved; a failing service is reported once and skipped.
• _disableFooter joins the other _disable* page switches.
• Command line split into Command/Arguments and Command/Actions; configuration rules moved to Configuration/Rules on the validator package; formatted HTML output and catalog pages.
• Sorting by key everywhere, API Markdown export without empty summaries.
• New suites for API export (exact output of every format) and the lexer's boundary cases.
• Complete wiki mirrors: every module, suite, and tool, with folder maps.
• Mutation testing leaves CI and runs by hand; closing survivors follows the first release.

Validation

• pudu check over src, test, tools, examples: no diagnostics
• pudu fmt --check and pudu lint: clean
• pudu test test: 15/15 suites, 474 assertions held
• Examples and examples/Cli.pudu build examples/site --force succeed; website builds (209 files)