refactor(#81): replace nudge button with always-visible count badge

Show the discussion count badge on every state (including 0) instead of
a separate nudge button. Simpler, less intrusive, and works without
needing an extra element near the panel.

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

frontend/src/lib/components/DocumentBottomPanel.svelte

@@ -107,7 +107,7 @@ function handleCountChange(count: number) {
 </script>
 
 <div
-	class="fixed relative right-0 bottom-0 left-0 z-30 flex flex-col border-t border-line bg-surface shadow-[0_-4px_16px_rgba(0,0,0,0.08)]"
+	class="fixed right-0 bottom-0 left-0 z-30 flex flex-col border-t border-line bg-surface shadow-[0_-4px_16px_rgba(0,0,0,0.08)]"
 	style="height: {panelHeight}px"
 	data-testid="bottom-panel"
 >
@@ -126,15 +126,6 @@ function handleCountChange(count: number) {
 		<div class="h-1 w-12 rounded-full bg-line"></div>
 	</div>
 
-	{#if !open && discussionCount === 0}
-		<button
-			data-testid="discussion-nudge"
-			onclick={() => openTab('discussion')}
-			class="absolute -top-7 left-1/2 -translate-x-1/2 rounded-full border border-line bg-surface px-3 py-1 font-sans text-xs whitespace-nowrap text-ink-3 shadow-sm transition-colors hover:text-ink"
-			>{m.comment_start_discussion()}</button
-		>
-	{/if}
-
 	<!-- Tab bar -->
 	<div class="flex shrink-0 items-center border-b border-line bg-surface px-4">
 		{#each tabs as tab (tab.id)}
@@ -146,7 +137,7 @@ function handleCountChange(count: number) {
 				aria-pressed={activeTab === tab.id && open}
 			>
 				{tab.label()}
-				{#if tab.id === 'discussion' && discussionCount > 0}
+				{#if tab.id === 'discussion'}
 					<span
 						data-testid="discussion-count-badge"
 						class="ml-1.5 inline-flex h-4 min-w-4 items-center justify-center rounded-full bg-primary px-1 font-sans text-[10px] font-bold text-white"

frontend/src/lib/components/DocumentBottomPanel.svelte.spec.ts

@@ -1,6 +1,6 @@
 import { describe, it, expect, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
-import { page, userEvent } from 'vitest/browser';
+import { page } from 'vitest/browser';
 import DocumentBottomPanel from './DocumentBottomPanel.svelte';
 import type { Comment } from '$lib/types';
 
@@ -30,45 +30,18 @@ const baseProps = {
 };
 
 describe('DocumentBottomPanel – discussion badge', () => {
-	it('shows a badge with comment count on the Discussion tab when comments exist', async () => {
+	it('always shows a badge on the Discussion tab', async () => {
+		render(DocumentBottomPanel, { ...baseProps, comments: [], open: true });
+		await expect.element(page.getByTestId('discussion-count-badge')).toBeInTheDocument();
+		await expect.element(page.getByTestId('discussion-count-badge')).toHaveTextContent('0');
+	});
+
+	it('shows the correct count when comments exist', async () => {
 		render(DocumentBottomPanel, {
 			...baseProps,
 			comments: [makeComment('c-1'), makeComment('c-2')],
 			open: true
 		});
-		await expect.element(page.getByTestId('discussion-count-badge')).toBeInTheDocument();
 		await expect.element(page.getByTestId('discussion-count-badge')).toHaveTextContent('2');
 	});
-
-	it('does not show badge when there are no comments', async () => {
-		render(DocumentBottomPanel, { ...baseProps, comments: [], open: true });
-		await expect.element(page.getByTestId('discussion-count-badge')).not.toBeInTheDocument();
-	});
-});
-
-describe('DocumentBottomPanel – start discussion nudge', () => {
-	it('shows nudge above drag handle when panel is closed and no comments', async () => {
-		render(DocumentBottomPanel, { ...baseProps, comments: [], open: false });
-		await expect.element(page.getByTestId('discussion-nudge')).toBeInTheDocument();
-	});
-
-	it('does not show nudge when panel is closed but comments exist', async () => {
-		render(DocumentBottomPanel, {
-			...baseProps,
-			comments: [makeComment('c-1')],
-			open: false
-		});
-		await expect.element(page.getByTestId('discussion-nudge')).not.toBeInTheDocument();
-	});
-
-	it('does not show nudge when panel is open', async () => {
-		render(DocumentBottomPanel, { ...baseProps, comments: [], open: true });
-		await expect.element(page.getByTestId('discussion-nudge')).not.toBeInTheDocument();
-	});
-
-	it('opens the discussion tab when the nudge is clicked', async () => {
-		render(DocumentBottomPanel, { ...baseProps, comments: [], open: false });
-		await userEvent.click(page.getByTestId('discussion-nudge'));
-		await expect.element(page.getByTestId('bottom-panel-content')).toBeInTheDocument();
-	});
 });