Replace raw Parent Workspace ID text input with a <select> populated
from GET /workspaces (T{tier} · {name} format, graceful fallback on
fetch error). Raise all interactive button text from text-[8px]/[9px]
to text-[11px] across SkillsTab, ScheduleTab, secrets-section,
ActivityTab, SidePanel, ChatTab; non-interactive labels/badges to
text-[10px]. Adds 7 CreateWorkspaceDialog unit tests (372/372 passing).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>