feat(web): add workspace management UI (M2 #12)

- Create workspace listing page at /settings/workspaces
  - List all user workspaces with role badges
  - Create new workspace functionality
  - Display member count per workspace

- Create workspace detail page at /settings/workspaces/[id]
  - Workspace settings (name, ID, created date)
  - Member management with role editing
  - Invite member functionality
  - Delete workspace (owner only)

- Add workspace components:
  - WorkspaceCard: Display workspace info with role badge
  - WorkspaceSettings: Edit workspace settings and delete
  - MemberList: Display and manage workspace members
  - InviteMember: Send invitations with role selection

- Add WorkspaceMemberWithUser type to shared package
- Follow existing app patterns for styling and structure
- Use mock data (ready for API integration)

apps/web/src/components/knowledge/EntryViewer.tsx

@@ -0,0 +1,39 @@
+"use client";
+
+import React from "react";
+import type { KnowledgeEntryWithTags } from "@mosaic/shared";
+
+interface EntryViewerProps {
+  entry: KnowledgeEntryWithTags;
+}
+
+/**
+ * EntryViewer - Displays rendered markdown content
+ */
+export function EntryViewer({ entry }: EntryViewerProps): JSX.Element {
+  return (
+    <div className="entry-viewer">
+      <div className="entry-content">
+        {entry.contentHtml ? (
+          <div
+            className="prose prose-sm max-w-none dark:prose-invert"
+            dangerouslySetInnerHTML={{ __html: entry.contentHtml }}
+          />
+        ) : (
+          <div className="whitespace-pre-wrap text-gray-700 dark:text-gray-300">
+            {entry.content}
+          </div>
+        )}
+      </div>
+
+      {entry.summary && (
+        <div className="mt-6 p-4 bg-gray-50 dark:bg-gray-800 rounded-lg">
+          <h3 className="text-sm font-semibold text-gray-700 dark:text-gray-300 mb-2">
+            Summary
+          </h3>
+          <p className="text-sm text-gray-600 dark:text-gray-400">{entry.summary}</p>
+        </div>
+      )}
+    </div>
+  );
+}