[CI] Automate binary builds and prerelease publishing

[CaseyLabs]

Summary

• publish release binaries only after changes land on master
• allow manual test releases through workflow_dispatch
• publish workflow-created releases as prereleases, never as Latest
• upload per-platform binaries, a _datafiles archive, and a checksum manifest
• document the downstream prerelease flow and ignore generated bin/ output

Example

Why

• release binaries should not be produced during PR iteration
• downstream still needs a way to test the release path without merging to master
• separate assets are easier for end users than a single all-in-one bundle
• manual test releases need safe, predictable generated tags
• release publishing should avoid a third-party action in the write-token step

Trigger Model

• PRs do not run the release workflow
• pushes to non-master branches do not run the release workflow
• pushes to master do run the release workflow
• workflow_dispatch can run the same release flow manually for downstream testing
• each release gets a generated prerelease tag using UTC time plus the commit SHA
• optional manual release_label values are validated as [A-Za-z0-9._-]+
• manually generated release tags are pinned to the dispatched commit SHA

Implementation

• switch the release workflow trigger from tag pushes to pushes on master
• add workflow_dispatch with an optional safe release_label suffix
• compute generated prerelease metadata in a prep job
• keep the binary's embedded version tied to the semver in main.go
• publish releases with GitHub CLI gh release create
• keep releases marked as prereleases and not Latest
• use GitHub-generated release notes
• update .github/RELEASING.md for the new downstream prerelease process
• ignore generated bin/ build output
• upload these assets:
  • gomud-ALL-datafiles-<generated-tag>.zip
  • gomud-windows_x64.exe
  • gomud-darwin_arm64
  • gomud-darwin_x64
  • gomud-linux_x64
  • gomud-linux_arm5
  • gomud-<generated-tag>-SHA256SUMS.txt

Validation

• actionlint .github/workflows/build-and-release.yml
• yamllint .github/workflows/build-and-release.yml
• make ci-local
• make js-lint
• focused bash and zsh checks for the release_label validation pattern

Stacking

• upstream-ready branch replays the downstream stacked release commits onto upstream/master

Upstream Move

• moved from downstream draft PR: Feature: Automate prerelease publishing and binary builds clabs-public-forks/GoMud#12
• replayed only the release automation commits from fix/windows-release-build..test/release-prerelease-automation onto upstream master
• upstream Windows-build prerequisite is tracked separately in [CI] Fix: Windows-specific build failure #488

[Volte6]

Small request for change in the README.md language

[Volte6]

Looks good