The user's WezTerm build (20240203-110809) rejects `initial_value` as a
PromptInputLine field (only `action`/`description` are valid on that
version), so constructing the action errored out immediately and the
whole callback died silently -- the prompt never appeared and the
underlying shell showed through. Current values are now shown inline
in the description text instead.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>