perf(docs): replace full lucide barrel import with explicit icon whitelist

Fixes #1241

The docs bundle was importing `{ icons }` from lucide-react, which pulls
the entire Lucide icon library (~1 400 SVGs, ~500 kB of JS) into the Next.js
docs bundle even though only nine icons are used in docs frontmatter and
meta.json files.

Replace with a hand-maintained DOCS_ICONS whitelist that imports only the
icons that are actually referenced (BookOpen, ClipboardCheck, Compass,
Container, Download, FlaskConical, Heart, Unplug, Wrench).

To add a new docs icon: import it from lucide-react and add it to the
DOCS_ICONS record. The icon() callback remains the same for callers.

surfsense_web/lib/source.ts

@@ -1,12 +1,39 @@
 import { loader } from "fumadocs-core/source";
-import { icons } from "lucide-react";
+import {
+	BookOpen,
+	ClipboardCheck,
+	Compass,
+	Container,
+	Download,
+	FlaskConical,
+	Heart,
+	Unplug,
+	Wrench,
+} from "lucide-react";
 import { createElement } from "react";
 import { docs } from "@/.source/server";
 
+/** Explicit whitelist of Lucide icons used in docs frontmatter / meta.json.
+ * Importing the full `icons` barrel would pull every Lucide icon (~1 400 SVGs)
+ * into the docs bundle even though only a handful are referenced. Add new icons
+ * here as docs pages are added.
+ */
+const DOCS_ICONS: Record<string, React.ComponentType> = {
+	BookOpen,
+	ClipboardCheck,
+	Compass,
+	Container,
+	Download,
+	FlaskConical,
+	Heart,
+	Unplug,
+	Wrench,
+};
+
 export const source = loader({
 	baseUrl: "/docs",
 	source: docs.toFumadocsSource(),
 	icon(icon) {
-		if (icon && icon in icons) return createElement(icons[icon as keyof typeof icons]);
+		if (icon && icon in DOCS_ICONS) return createElement(DOCS_ICONS[icon]);
 	},
 });