plugin.json: add displayName, so catalogues stop calling it "Html2Wp Cc Plugin"

marketplace.json has carried displayName for a while, but plugin.json never
did — and the catalogues read plugin.json. aitmpl's generator picks the name
in this order: plugin.json displayName, then the marketplace name, then the
plugin name, each of the last two only if it looks human-written. "html2wp"
is a lowercase slug, so it failed both tests and fell through to the last
resort, which title-cases the repository name: "Html2Wp Cc Plugin".

Same string as marketplace.json already uses, so the two cannot drift.

No version bump: nothing under skills/ or hooks/ changed, and catalogues
fetch this manifest live, so it reaches them on their next generation.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TUTXEuPnmJpuncXLFBSnXQ

Author: BELNEM s.r.o

.claude-plugin/plugin.json

@@ -1,5 +1,6 @@
 {
   "name": "html2wp",
+  "displayName": "html2wp — HTML to WordPress",
   "description": "BETA. Convert a static HTML site — or anything that builds to one (Lovable, Bolt, v0, Next export) — into a standalone WordPress block theme: verified pixel by pixel, pages, blog, forms, menus, SEO and redirects, with no plugin required and verification gates at every stage. Every conversion ends in your own page-by-page review; the gates catch most fidelity drift, not all of it.",
   "version": "1.0.0-beta.26",
   "author": {