Versioning (Axion Release Plugin) + publication config

[roxspring]

Wire up automated semver versioning and Maven publication.

Scope

• Axion Release Plugin — git-tag-driven semver
• Maven publication config for library module (sources JAR, javadoc JAR)
• Gradle plugin publication config for gradle-plugin module
• Plugin ID registered: net.oxspring.markflow
• Group ID: net.oxspring.markflow

Versioning strategy

Commit-message driven automatic releases via Conventional Commits — no manual release step:

Commit prefix	Effect
fix:	Patch bump → release
feat:	Minor bump → release
feat!: / BREAKING CHANGE:	Major bump → release
chore:, docs:, test:, refactor:	No release

Axion's custom version incrementer reads the commit log since the last tag to determine the bump level. Requires fetch-depth: 0 in CI checkout (noted in issue #1).

Notes

• Initial publication target: GitHub Packages (https://maven.pkg.github.com/roxspring/markflow) — no auth friction for the owner, acceptable for early adopters
• Maven Central + Gradle Plugin Portal deferred to a later milestone when API stabilises
• Gradle plugin module directory: gradle-plugin/ — internal package: net.oxspring.markflow.gradle