Give feedback on a night #112

Blocked by: #107

Problem

The manager often knows something the model doesn't, and needs a quick way to say a rate is wrong, what they'd charge instead, and why, both before a night and after it.

Goal

From the night detail page, the manager says whether the rate is too high, too low or about right, optionally gives their own rate and a reason, and can change it later.

Scope

• A feedback form on the night detail page:
  • verdict: too high, too low, about right;
  • optional rate they'd charge (€);
  • reason (see the open question below);
  • save.
• Works for future and past nights; the wording changes for past nights (e.g. "What should this night have been?").
• Show the current feedback and let the manager change it; show when it was last changed.
• After saving, the calendar and detail page show the manager's rate without a page reload.
• Show the API's validation message if saving fails.

Design

• No design exists yet. Design the form inside the night detail page before building.
• Keep it to a few taps for the common case ("about right").
• Open question: how the manager gives a reason: a fixed list of tags (e.g. group or wedding block, venue sold out, competitor pricing, local knowledge, other), free text, or both. Agree it with the backend.

Acceptance criteria

• The design is agreed before building.
• Feedback can be saved on a future and a past night (against mocks until the backend is ready).
• Changing feedback shows the new version and when it changed.
• A saved rate shows on the calendar and detail page straight away.
• A rate of 0 or less can't be submitted.