fix: wiki index no longer bumps right; harden Harmony Inter/Poppins fonts

#30 — namespace index / section listing pages had their heading, lead, and
page list pushed into a narrow centered column with a big left gutter. The
listing card reuses the .wiki-article-prose class, so the article-body reading
treatment leaked onto it: the wiki plugin caps prose children at
--wiki-prose-measure (54rem) and the theme margin-inline:autos them. Opt the
.wiki-namespace-index card out of that measure/centering so the listing runs
full-width and left-aligned. Verified with a before/after render of the real
section markup against the compiled CSS.

Inter 404 (sow-nodebb#13) — Harmony emits Inter/Poppins @font-face at our asset
path and points its sans/secondary font vars at them, but we ship Jost + Cinzel
and declare no @fontsource/inter|poppins dep, so those URLs 404 in production
(they only resolve in dev via npm hoisting). Pin the Harmony rules that read
those vars directly (.ff-sans, .ff-secondary, breadcrumb divider) to our fonts
so nothing can request Inter/Poppins, and drop the two dead staticDirs. The live
404 clears once the nodebb image is rebuilt from current theme main.

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

plugin.json

@@ -20,8 +20,6 @@
     "../client/account/theme.js": "../nodebb-theme-harmony/public/settings.js"
   },
   "staticDirs": {
-    "inter": "node_modules/@fontsource/inter/files",
-    "poppins": "node_modules/@fontsource/poppins/files",
     "fonts": "public/fonts",
     "game-icons": "public/game-icons",
     "images": "public/images"