feat: add table support to TipTap editor

Install @tiptap/extension-table packages, register Table/TableRow/
TableHeader/TableCell extensions, add Table button to the More dropdown
(inserts a 3×3 grid), and style tables to match the parchment theme.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/components/FormattingToolbar.svelte

@@ -23,7 +23,8 @@
 		AlignJustify,
 		Minus,
 		ChevronDown,
-		Ellipsis
+		Ellipsis,
+		Table2
 	} from 'lucide-svelte';
 
 	interface Props {
@@ -338,6 +339,14 @@
 					<CodeXml size={iconSize} />
 					<span>Code block</span>
 				</button>
+				<button
+					onclick={() => { editor?.chain().focus().insertTable({ rows: 3, cols: 3 }).run(); closeDropdowns(); }}
+					class={dropdownItemClass()}
+					data-testid="format-table"
+				>
+					<Table2 size={iconSize} />
+					<span>Table</span>
+				</button>
 				<button
 					onclick={() => { editor?.chain().focus().setHorizontalRule().run(); closeDropdowns(); }}
 					class={dropdownItemClass()}

src/lib/components/TiptapEditor.svelte

@@ -6,6 +6,10 @@
 	import Underline from '@tiptap/extension-underline';
 	import TextAlign from '@tiptap/extension-text-align';
 	import Placeholder from '@tiptap/extension-placeholder';
+	import { Table } from '@tiptap/extension-table';
+	import { TableRow } from '@tiptap/extension-table-row';
+	import { TableHeader } from '@tiptap/extension-table-header';
+	import { TableCell } from '@tiptap/extension-table-cell';
 	import { Markdown } from 'tiptap-markdown';
 
 	interface Props {
@@ -30,6 +34,10 @@
 				Underline,
 				TextAlign.configure({ types: ['heading', 'paragraph'] }),
 				Placeholder.configure({ placeholder }),
+				Table.configure({ resizable: false }),
+				TableRow,
+				TableHeader,
+				TableCell,
 				Markdown
 			],
 			content,