[html4tree Quality Gap] Enforce production line and branch coverage plus API documentation

[seonghobae]

Current gap

ContextualWisdomLab/html4tree/build.gradle enables JaCoCo and sets one unqualified minimum = 1.00 limit. JaCoCo's default counter and element do not make the intended production line and branch contracts explicit, and the current build has no public Kotlin API/KDoc gate.

The organization requirement is stronger: production statement/line coverage 100%, production branch coverage 100%, and complete documentation for shipped public APIs. A single implicit bundle-level limit can hide exactly which counter regressed and can include or exclude generated/synthetic code without a reviewed policy.

Required contract

Coverage

• Define explicit JaCoCo verification limits for production LINE and BRANCH counters.
• Keep test code and generated build artifacts out of the production denominator through a documented class-directory filter.
• Publish XML and HTML evidence on every pull request.
• Fail when the report is missing or when any production file is absent from the report.
• Report missed lines and branches with file and line context.
• Add a mutation or negative control test proving that removing a branch test makes the gate fail.

Public documentation

• Define which top-level functions, classes, properties, CLI options, and error types are supported public APIs.
• Require KDoc for every supported public symbol, including security and destructive-operation behavior.
• Treat deliberately internal implementation as private/internal rather than documenting accidental public visibility.
• Generate and validate Dokka output without unresolved links or undocumented supported symbols.

Realistic tests

• File-system enumeration failure
• Metadata-read failure
• user-authored index.html preservation
• symlink and root-boundary refusal
• mixed-direction and hostile Unicode names
• HTML escaping and URL encoding
• atomic and fallback publication behavior
• CLI exit codes and destructive-option confirmation

Compatibility and release gate

• Upgrade JaCoCo/Dokka/Gradle only through an explicit compatibility plan for the Kotlin and Java versions actually supported.
• Do not weaken the denominator to obtain green coverage.
• Update AGENTS.md, CHANGELOG.md, and doctoring references.
• No release may claim 100% production coverage or documentation until the exact explicit counters and symbol inventory pass on the release commit.

Evidence

Current build configuration: https://github.com/ContextualWisdomLab/html4tree/blob/master/build.gradle

Priority

High. This is a release-governance gap required by the organization development contract.