Make the app work end to end #72

Problem

The frontend, API, hotel data, model and auth work is split across separate issues. Each piece can be finished and still not add up to something the manager can use.

Goal

On the deployed app, the manager can log in, upload the day's PMS exports, see the next 30 nights with recommended rates that reflect the latest events, open a night to see why it's priced that way, and send feedback that changes later recommendations.

Scope

• One sub-issue per step of that flow. Each is blocked by the frontend and backend issues it needs, and is done when the step works on production.
• Fixing the gaps found while connecting the pieces.

Considerations

• This is where frontend and backend meet. Agree request and response shapes early so both sides can build in parallel against mocks.

Acceptance criteria

• All sub-issues are closed.
• Someone who didn't build it can walk through the whole flow on production with the hotel's real data.