[bug] registry + label bot don't recognise the [family-assembly] title prefix

[BenchCAD]

Two prefix parsers don't know the [family-assembly] title convention (#53, #54, and now #26/#42 use it):

• .github/scripts/gen_registry.py title regex is \[(?:family|proposal)\] — a [family-assembly] issue silently drops out of registry.json. Evidence: t_handle_ball_lock_pin ([family-assembly] t_handle_ball_lock_pin #53, open) is absent from registry.json on main.
• .github/workflows/label-issues.yml extracts the tag with [([a-zA-Z]+)] — no hyphen, so the bot never fires on these issues, and the prefix has no entry in its label map anyway.

Fix: accept family-assembly in the registry regex; let the label regex match hyphens and map family-assembly → the same family label.