,, becomes one-shot: top fix on the prompt line, --pick for alternatives

[FrancoisChastel]

Summary

Before this PR, ,, always opened the fzf picker, even for obvious typos (-tpye → -type). One keystroke too many for the common case. And ,, <prompt> was overloaded — sometimes "fix with intent", sometimes "propose with context" — which left the model guessing.

After:

Invocation	Behavior
,,	One-shot fix. Top suggestion drops on the prompt line; diagnosis prints above. User reads both, hits Enter to run, or edits, or Ctrl-C. Never auto-executes.
,, <intent>	Same flow, but the intent narrows the model (,, use ripgrep, ,, I meant the dev branch).
,, --pick [intent]	Escape hatch — full picker for ambiguous cases where alternatives matter.
, --ctx <prompt>	The old "propose with context" use case — moves to a flag on , since it's refinement, not repair.

What changed

• comma.py adds --pick. In fix mode the default path is now chosen = items[0]["command"], skipping _pick() entirely; --pick restores the picker.
• The ,, zsh function always invokes --fix. It pops a leading tier flag (--fast/--balanced/--smart) for routing, recognises --pick anywhere in the args, and treats everything else as intent.
• Bash adapter (llmf) mirrors the same shape.
• The , --ctx <prompt> flag already existed; the migration is documentation telling users where to go.

The comma never executes invariant stays intact: print -z puts the command on the next prompt line; the user's finger on Enter is what runs it.

Demo

Beat 2 is one keystroke shorter — diagnosis line and the corrected find . -type f -name '*.py' land together. The audience reads both, then Enter to run. New gif rendered, committed in this PR.

Test plan

• pytest -q clean (264 tests, 4 new):
  • bare --fix prints top suggestion to stdout, does not invoke _pick
  • --fix --pick restores the picker path
  • --pick coexists with a free-form intent (both reach the model)
  • plain , still uses the picker
• ruff check and ruff format --check clean
• Demo renders end-to-end with no-picker fix flow visible
• Manual: source updated zsh/shellllm.zsh, run a failing command, verify ,, drops the corrected command on the prompt line ready for Enter