Setup wizard does not persist Octopus Energy provider selection

[johanzander]

Problem

When an Octopus Energy user completes the setup wizard, the energy provider remains set to nordpool_official with an empty config_entry_id. The system cannot fetch any price data and fails to initialize.

Evidence

From debug log in #60:

Failed to serialize price data: Failed to get price data: Nordpool integration not configured: config_entry_id is missing.

Stored config shows:

• "provider": "nordpool_official" (should be "octopus")
• "octopus": {} (empty — no entity IDs persisted)
• Discovery correctly returned octopus_found: true

The user's API calls show only POST /api/setup/confirm, never POST /api/setup/complete.

Root Cause

ConfirmSetupPayload in api_dataclasses.py only accepts sensors, nordpool_area, nordpool_config_entry_id, and growatt_device_id. There is no field for energy provider or Octopus entity IDs. Only APISetupCompletePayload (used by /api/setup/complete) has these fields.

The frontend wizard uses /api/setup/confirm which silently drops the provider selection.

Fix

Either:

1. Add provider and Octopus entity fields to ConfirmSetupPayload, or
2. Ensure the frontend wizard calls /api/setup/complete instead of /api/setup/confirm, or
3. Auto-set provider to octopus when discovery detects Octopus and no Nordpool

Ref

Reported by @GraemeDBlue in #60.

[GraemeDBlue]

the problem is the Octopus wizard is asking for fields my Octopus integration does not have due to my Octopus Flux Import and Octopus Flux Export Tarrifs