UX-13 P4: the setup wizard for installers

The Setup tab draws the Installer view's page model one step at a time,
from each field's `wizard` step in app/uilayout.py: meter (with the kettle
test), inverters and batteries, solar (optional), prices, peak limit
(battery modes: "comes in a later update", OPT-11), check and start.
It reuses P2's controls and saves through /config/validate and
/config/save. No route was added.

- First run: /config/model says `setup_needed` when the stored options name
  no power request entity, or on a new install (no `setup_done` and no
  `auto` in the Store, control not started). The page opens #setup only
  when opened with no route. The wizard's save writes `setup_done`.
- Kettle test: GET ha/entities?entity= reads one entity now, in W. The
  change decides: up keeps meter_invert off, down turns it on; a net or
  import/export meter that goes down blocks the step with what to check.
- Last step: validate.setup_checks() beside the refusals: the meter reads,
  each power request entity exists in HA (bad if not, SAFETY-77), battery
  levels and power with direction, solar sign, prices. Saves with
  shadow_mode on by default, then a confirmed restart naming the 0 W.
- P2 test finding (a): a stale save lists only the keys the other surface
  moved (the blob handed out on open, by fingerprint, against stored now).
- test_setup.py; tools/ux13_wizard_blobs.py makes the 88 blobs the wizard
  can save; all accepted by Supervisor 2026.08.0 AppOptions (offline).
- DECISIONS/UX-13-setup-wizard.md; DOCS "Setup, for a new install".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LyR88rXETvwhTgx6yHE39p

goodwe_controller/DOCS.md

@@ -3221,6 +3221,32 @@ action log (`Controller.events`). The page no longer shows that log, but the
 page and add `status` to its address. The action-log tables in this document
 refer to it.*
 
+### Setup, for a new install
+
+The **Setup** tab walks an installer through six steps: the meter, the
+inverters and batteries, solar (optional), prices, the peak limit, and a last
+check. Each step shows the same fields as Settings, and nothing is saved until
+the last step.
+
+- **The kettle test** on the meter step reads the meter, then reads it again
+  after you switch on a kettle. If the reading goes down, the add-on flips its
+  sign for you; with a net or import/export meter it tells you what to change.
+- **The last step** runs the add-on's own start checks and reads Home
+  Assistant: the meter reading, that each power request entity exists, the
+  battery levels, and whether prices are known. A missing power request entity
+  is red, so it cannot be saved.
+- **Save and restart** saves, then restarts the add-on. Every inverter is set
+  to 0 W while it restarts, and with "Start in shadow mode" on (the default) it
+  stays at 0 W until you turn shadow mode off under Settings.
+
+Setup opens by itself when the page is opened on a new install: control was
+never started or stopped and Setup never finished, or the stored settings name
+no inverter to control. A running site is never sent there. The add-on does
+not start with no power request entity at all, so on a brand-new install fill
+in "Inverter setpoint entity" on the Configuration tab first.
+
+*For installers: card UX-13, and `DECISIONS/UX-13-setup-wizard.md`.*
+
 ## Status page
 
 The add-on page shows a banner at the top and a **Commissioning** list below