docs: rephrase the vale warnings that have a better wording

Words the alex and Microsoft styles flag where a plainer one reads as well:
disabled/special/invalid as a state, primitive, trap, hang, several, click,
first-person FAQ questions, hyphenated adverb pairs. Left as they are: Let's
Encrypt, quoted UI labels and phrases, the generated forge CLI reference, and
the middle-click gesture.

docs/web-ui/README.md

@@ -92,7 +92,7 @@ JS renders — no full-page reloads.
   motion, theming, error-UX, and component-first principles for the
   swarm-level Preact app specifically (not this page's dashboard/agent
   UIs). `/components` on a running swarm-ui is the companion living
-  demo of every primitive it references.
+  demo of every building block it references.
 
 ### Implementation reading paths
 
@@ -115,6 +115,6 @@ touching the code rather than using the UI:
   [`agent.md`](agent.md) (Terminal-embedded prompt).
 - **"What are the per-agent HTTP endpoints?"** →
   [`agent.md`](agent.md) (Per-agent endpoints).
-- **"Which CSS variable do I use / where are colours defined?"** →
+- **"Which CSS variable to use / where are colours defined?"** →
   [`css-vars.md`](css-vars.md) (Palette, single-source `base.css`
   rule).