release: 1.8.0: Built-in operator help drawer and /help page

Built-in operator documentation in the panel: a CSS-only help drawer and Help page so Status checks and domain controls are explained without leaving the panel.
Added:
  - **Help** navigation entry and `/help` index page.
  - CSS-checkbox help drawer (no extra script): seeded topics for Status (Machine,
  - «?» entry points on Status and domain card heads open the matching drawer
Changed:
  - [guide.md](docs/guide.md) documents the boundary: in-panel help for card

Full detail: CHANGELOG.md (1.8.0).

internal/web/view/templates/status.html

@@ -3,7 +3,10 @@
 {{define "wide"}}wide{{end}}
 
 {{define "content"}}
-<h1>Status</h1>
+<div class="page-head">
+  <h1>Status</h1>
+  <label class="help-link" for="help-status" title="What these checks mean">?</label>
+</div>
 
 {{if .Flash}}<div class="flash">{{.Flash}}</div>{{end}}