DOC-1: operator docs name the real P1 entity and a roster that starts

- DOCS.md / config.yaml: the watchdog's P1 age entity is
  sensor.goodwe_p1_sample_age (device "GoodWe" + "P1 sample age", as
  app/mqtt.py announces and the live install recorded), not
  sensor.p1_sample_age_s.
- DOCS.md: the inverters: example and per-entry table carry the required
  bms_soc_floor (and capacity_kwh); config.yaml's schema comment says four
  required keys, not three.
- Field guide: marked v0.1.0/outdated; slew_w row no longer recommends the
  1000 W that SAFETY-39 now refuses. HTML regenerated; the PDF is NOT
  rebuilt (no Chrome here). README/DOCS pointers fixed.
- test_docs.py: the documented roster must pass app/validate.py and the
  schema's per-entry keys; the documented entity id must equal the id
  composed from app/mqtt.py; the wrong id may appear in no shipped doc.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU

docs/build_guide.py

@@ -95,7 +95,7 @@ figcaption { font-size:9pt; color:#5b6169; margin-top:1.2mm; }
 <div class="page" id="p1">
   <div class="hdr">
     <div><h1>GoodWe RS485 Controller</h1>
-         <div class="sub">Field installation &amp; commissioning guide — v0.1.0</div></div>
+         <div class="sub">Field installation &amp; commissioning guide — v0.1.0, <b>outdated</b>: where it disagrees with DOCS.md, DOCS.md wins</div></div>
     <small>Installer copy</small>
   </div>
 
@@ -503,7 +503,7 @@ figcaption { font-size:9pt; color:#5b6169; margin-top:1.2mm; }
   <table>
     <tr><th style="width:30mm">Setting</th><th style="width:16mm">Value</th><th>Reason</th></tr>
     <tr><td><code>gain</code></td><td>0.6</td><td>Inverter needs 3–6 s to settle (1.4 s dead time, 94 % by 3.3 s) against a ~5 s cycle. <b>At the limit — do not raise</b></td></tr>
-    <tr><td><code>slew_w</code></td><td>1000</td><td>Most of a correction in the first cycle without running far ahead of the hardware</td></tr>
+    <tr><td><code>slew_w</code></td><td>0</td><td>0 follows the rail (<code>max_w</code>&nbsp;/&nbsp;9). A faster fixed value is <b>refused at startup</b> (SAFETY-39) — see DOCS.md</td></tr>
     <tr><td><code>deadband_w</code></td><td>15</td><td>Measured residual: mean 15.4 W, max 27 W. At 10 W the command never rests</td></tr>
     <tr><td><code>saturation_w</code> / <code>cycles</code></td><td>500 / 3</td><td>Divergence = inverter at a limit → magnitude may fall, never rise. <b>The 3-cycle term is essential</b>: tested instantly it fires on every large correction</td></tr>
     <tr><td><code>step_w</code></td><td>10</td><td>Register is 1 W but response lands on a ~17.6 W ladder. Finer is meaningless</td></tr>