fix(printer): preserve JSON and HTML response content

[rupayon123]

Problem and change

Preserve JSON and HTML response content during formatting. JSON keys and string values are escaped correctly, actual written byte counts include partial writes, and trailing documents/junk/read errors are reported rather than silently ignored. HTML formatting preserves script/style raw text, namespace-qualified attributes, and preformatted whitespace, including a leading newline.

Response selection now parses the media type itself: structured +json and XHTML bodies reach their formatters instead of being hidden as binary data, and a MIME parameter cannot accidentally select the JSON or HTML formatter.

Validation

Focused regressions reproduced every original failure. Full env -u NO_COLOR go test ./..., go vet ./..., builds, formatting and git diff --check pass. Regression cases include JSON round trips and failing writers/readers, HTML parse-format-parse content comparisons, namespaced attributes, and response media-type dispatch. Color environment isolation is submitted separately in PR39. golangci-lint was not run locally.

Prepared with AI assistance. Remote CI is verified separately on the latest head; passing checks do not imply maintainer approval.

[rupayon123]

Additional fixes pushed to this branch:

• f996ae7: Preserve HTML doctype public and system identifiers.
• c2ff913: Detect actual HTML document tags without mistaking comments, raw text or tag-name prefixes for wrappers.

Full Go tests, go vet and build pass. Regressions verify PUBLIC/SYSTEM doctype identifiers and prevent document wrappers from being inferred from comments, script text or html-prefixed custom tags. Today's changes have no new findings under golangci-lint v2.13.2 using a migrated copy of the repository configuration. This is a scoped lint result: a full CLI-branch scan still reports 93 findings outside today's changes; the legacy v1 linter cannot read the installed Go 1.27 export format.

Prepared with AI assistance. Changes are submitted for review; this is not a claim of maintainer approval.

[rupayon123]

September 16 verified update:

XML media types now render as text. Three regressions failed before the fix; the full Go suite, vet, build and scoped lint pass after it.

Commits: a6438eb89b1789335ee4fb28b30ae61f103bc44a.

Exact current head: a6438eb89b1789335ee4fb28b30ae61f103bc44a. GitHub checks at this read: build: SUCCESS. Local results do not imply maintainer approval.

AI-assisted with OpenAI Codex; changes and validation were inspected before submission.