feat(tasks): add task-to-task relations (blocks / duplicates / relates) (#224)

Empty release-trigger commit. The feature itself landed on main in the
#222 promotion, but the squash commit was typed chore(release), which
release-please ignores when computing releases - so no v14.2.0 release
PR was proposed. This commit restates the feature with its original
conventional message so release-please proposes v14.2.0 with a proper
changelog entry.

Refs: #221, #222

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: parth0025