UX-13 P1: page shell and Home screen on a structured /status

- app/static/{index.html,app.css,app.js}: tabs (Home, Batteries, Settings,
  Setup), hash routes, phone bottom tabs, light/dark. Served inlined at "/";
  the route list is unchanged, and every URL is relative.
- app/homeview.py: /status gains state, now, batteries, plan, attention,
  month_peak and control beside the old fields. The plan is what the add-on
  does today: the arbitrage verdict (the same plan.arbitrage() call as the
  cycle), the monthly cycle, the peak limit, "follows the house".
- The Home plan chart has hover, tap and keyboard-focus tooltips: price bar =
  hour and price; block = what, when, why, kWh and EUR.
- Region preset and year: in config/model (for P2) and on the Home price line.
- test_home.py; test_messages part 8 scans every Home sentence; STYLE plan line.

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

STYLE.md

@@ -7,6 +7,7 @@ This applies to everything a home owner or installer reads: notifications, phone
 - **Body**: **one sentence** of at most 25 words, saying what happened and what to do. A **red alarm** may use up to **3 sentences** (70 words, each sentence at most 30 words), so that no action a person must take is lost.
 - **Details**: the last line links to the add-on documentation and names the section with the rest: `Details: add-on documentation, section "<title>" under Notifications.` Background, figures, reason codes and history go there or into the log, never into the body.
 - **Status row**: one sentence of at most 15 words. A **red** row may use up to 3 sentences (30 words), like a red alarm. It shows the live numbers the reader acts on and never an HA entity id. **Banner**: at most 12 words. **Refusal**: at most 30 words, naming the setting by its label and then its key, as `messages.setting()` writes it: “Inverter rating” (max_w), or “Inverter rating” for inverter-b (inverters.max_w) for one inverter in the list. **Option name**: at most 6 words, not counting the group prefix. **Option description**: at most 30 words. Where a value comes from belongs in DOCS.md.
+- **Plan line** (UX-13 Home screen: the plan, tooltips, a battery's "now" line): at most 2 sentences, each at most 12 words. Words from `app/homeview.py`, checked by `test_messages.py` part 8.
 - **Log line** (WARNING/ERROR): one line of at most 25 words **as logged**, with any built text filled in. Log lines stay in English and are not translated. A line that reports a safety reason gives one plain sentence and the reason's code (`STALE_READING`, `OUTPUT_CLAMP`), the evidence an installer searches for. The reason itself, with its figures and limits, goes on a DEBUG line right after it and into the action log, never onto the WARNING/ERROR line. It keeps the shape of a red alarm: at most 3 sentences of at most 30 words. The line as logged has no semicolon, banned word, capitals, "1 times" or "(s)". `test_messages.py` part 6 builds every such text with the real code and checks it, and lists the few non-safety families still over 25 words. A line that repeats every cycle is DEBUG. INFO lines carry no section numbers, ISO timestamps or capitals.
 - **Refusal length is counted as shown**: a setting placeholder counts as its label and key, and the long cases are driven through the validator (`test_messages.py` part 3).
 - **Event line** under the buttons: the plain words of `messages.hint()`, like a green row. The add-on's own action log stays technical and is not shown on the page. Installers read it as `events` in the `status` JSON.