chore: consolidate CI workflows and add full test suite

[theodevelop]

Type of change

• Bug fix
• New feature
• Refactor / internal improvement
• Docs / config only

What does this PR do?

Consolidates and fixes the CI/release workflows:

• ci.yml: adds workflow_dispatch (allows manual CI runs from any branch, useful for fork contributors) and runs all 6 test suites instead of only test-parsers.ts
• release.yml: replaces both the old release.yml and publish-ovsx.yml with a single consolidated workflow — one build, one job. Publishes to GitHub Release, Open VSX, and VS Marketplace. Each publish step skips gracefully if the corresponding PAT secret is not set. Adds a guard to ensure the tag is on main before proceeding.
• publish-ovsx.yml: deleted (superseded by release.yml)

Related issue

Closes #46

How to test manually

• Push a v* tag from main and verify all three publish steps run (or skip with a warning if PAT absent)
• Open a PR from a fork branch and trigger CI manually via Actions tab

Checklist

• npm run compile passes with no new errors
• Tests added or updated (npx ts-node ...)
• Manual test done in VS Code
• CHANGELOG.md updated
• No unintended files staged (node_modules, .env, dist...)

[GitMensch]

As it is "just ci" and the changed definitions need to be in the main branch to have an effect - could you bring that to "main" soonish?