Answer the decision with Druks gate controls

[czpython]

Stacked on #7. Merge that first, then retarget this PR to main.

Summary

The decision page drew its own outcome form: an app-owned ui.Form that posted to Panel's record_outcome route, which called RecordDecision.answer(). Druks now draws the controls for a subject's parked gate from the gate itself (czpython/druks#744). Panel asks for the call in-app and shows ui.GateControls(decision).

• Workflow: RecordDecision parks with {"presentation": "in_app", "label": "Record the decision"}. Druks offers the three DecisionAction values as controls. It shows a note box because the gate declares note. The ask also shows the run's latest artifact, which is the moderator's "Panel synthesis".
• Page: "The call" shows ui.GateControls(decision) until an outcome is recorded. The controls show nothing while the run is not parked. The page no longer reads the run status.
• Routes: the record_outcome route and DecisionOutcomeRequest are deleted. The answer reaches the workflow through the Druks gate route (POST /api/gates/{run}/answer), which holds the control to the offered values.

The Dashboard still sends the operator to the decision page: for an in-app ask, it opens the subject's page. The Druks subject page also shows the same controls.

Trade-offs

• The buttons show the raw values proceed, revise, and pass. The Druks shell has labels only for its own controls.
• Panel's form wording goes: the "Outcome" label and the "What the record must say about this call." hint. The Druks note box says a note is "sent to the agent as feedback". Here, the note is recorded with the outcome.
• The note loses Panel's 2,000-character limit and whitespace stripping.

Verification

Ran in a fresh environment with editable installs of Druks main (beed0baa) and this branch:

• ruff check, ruff format --check, pyright, and druks check-app panel: clean
• A throwaway check with the Druks pytest plugin (not committed, because this repo has no tests) seeded a run parked on record_decision with the ask Druks builds from Panel's in-app request. It covered these cases:
  • the decision page serves gate_controls for the decision. Its status is empty before the park and parked on record_decision after it.
  • GET /api/gates/{run} returns the label, controls: ["proceed", "revise", "pass"], and reply_fields: ["action", "note"]
  • the gate route refuses maybe with INVALID_GATE_ANSWER
  • an answer of revise with a note sends a payload on the record_decision topic that validates as a RecordDecision reply
  • POST /api/panel/decisions/{id}/outcome no longer exists
• Not run: a full deliberation against a live durable engine and model provider. The resume itself is the Druks gate path, which Panel's route also used.