docs: lead the token-efficiency point with the HTML surface

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: benvinegar

README.md

@@ -23,10 +23,11 @@ comment, revise: a two-way loop, right next to the conversation.
 - **See what your agent means.** An architecture it's proposing, a flow it's
   tracing, a UI it's about to build — shown, not described in a paragraph you
   have to picture in your head.
-- **Cheaper than hand-written HTML.** Surfaces are purpose-built part kinds —
-  mermaid, markdown, diff, terminal — so the agent hands over compact source and
-  the viewer renders it, spending far fewer tokens than generating raw HTML for
-  every output.
+- **Cheaper than raw HTML.** The agent writes an HTML surface as a bare body
+  fragment against the viewer's theme — no document boilerplate, no styling
+  scaffolding — so even the primary kind costs fewer tokens than hand-rolling a
+  page. Purpose-built kinds (markdown, diff, terminal, mermaid) trim it further
+  for the common cases.
 - **Comment instead of re-prompting.** Click a card, leave a note. The agent
   reads it and revises — no copy-pasting screenshots or re-describing what you
   meant.