Extract duplicate `TYPE_ICONS` constant from citation components into a shared module

[MODSetter]

Description

The exact same TYPE_ICONS record mapping CitationType to Lucide icons is defined twice, in two files:

1. surfsense_web/components/tool-ui/citation/citation.tsx (lines 13–20)
2. surfsense_web/components/tool-ui/citation/citation-list.tsx (lines 12–19)

Both definitions are byte-for-byte identical:

const TYPE_ICONS: Record<CitationType, LucideIcon> = {
	webpage: Globe,
	document: FileText,
	article: Newspaper,
	api: Database,
	code: Code2,
	other: File,
};

Both files import the same 6 Lucide icons (Globe, FileText, Newspaper, Database, Code2, File) for this map.

What to do

1. Create a new file, e.g. surfsense_web/components/tool-ui/citation/type-icons.ts:

import type { LucideIcon } from "lucide-react";
import { Code2, Database, File, FileText, Globe, Newspaper } from "lucide-react";
import type { CitationType } from "./schema";

export const TYPE_ICONS: Record<CitationType, LucideIcon> = {
	webpage: Globe,
	document: FileText,
	article: Newspaper,
	api: Database,
	code: Code2,
	other: File,
};

2. In both citation.tsx and citation-list.tsx:
   • Import TYPE_ICONS from "./type-icons"
   • Remove the local TYPE_ICONS definition
   • Remove the now-unused Lucide icon imports that were only used for TYPE_ICONS (keep any that are still used elsewhere in the file)

Verify after changes:

• Both Citation and CitationList components still render the correct type icons
• citation-list.tsx's OverflowItem and StackedCitations components still show correct icons
• next build succeeds

Acceptance criteria

• TYPE_ICONS is defined in exactly ONE place
• Both citation.tsx and citation-list.tsx import it from the shared module
• No duplicate Lucide icon imports remain