Remove redundant "Dashboard" nav bar entry

NavMenu rendered a static, non-functional "Dashboard" span alongside
Presets/Settings/Docs buttons. It didn't toggle any panel — the real
Dashboards content (App.tsx's <Dashboards />) is already always visible
in the main content area, so it needed no nav entry to be reachable.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o

webapp/src/components/NavMenu.tsx

@@ -60,7 +60,6 @@ export function NavMenu({ stats }: { stats: Stats | null }) {
           <div className="mb-4 text-lg font-semibold text-text">ottyl</div>
           <PresetsDropdown panel={panel} />
           <nav className="mt-2 flex flex-col gap-1 text-sm text-text-muted">
-            <span className="rounded bg-surface-2 px-2 py-1 text-text">Dashboard</span>
             <button
               type="button"
               onClick={() => togglePanel('settings')}