ci: the verify-full label forces the full run, also for doc-only PRs #89

Problem

The label verify-full does not run verify:full on a PR that changes only Markdown: the CI step "Detect changes" sets code=false for docs/** and *.md, and every expensive step – including verify:full – requires code=true. The release PR #86 (CHANGELOG, AGENTS.md, a skill file) therefore got no verify:full, although AGENTS.md requires it before a release. Adding the label to an open PR also triggers nothing: labeled is not among the workflow's event types.

Acceptance criteria

• A PR labelled verify-full runs install, verify and verify:full even when it changes only Markdown
• Adding the label to an open PR starts a run (labeled event)
• PRs without the label behave as before (doc-only PRs stay fast)

Security/Privacy affected?

No – CI only, no secrets involved.