refactor: remove legacy annotate mode — transcription replaces it

The yellow annotation+comment system is now redundant. Transcription
blocks handle the same use case (mark region → discuss) but better,
because they also produce a transcription.

Removed:
- annotateMode state and all wiring through page/topbar/viewer/pdfviewer
- Annotate/Stop annotate buttons from DocumentTopBar
- AnnotateHintStrip import and rendering
- AnnotationSidePanel from document detail page
- canAnnotate prop from DocumentTopBar
- Color picker from PdfViewer
- Comment count badges and loadCommentCounts from PdfViewer
- Delete button from AnnotationLayer (blocks own annotation lifecycle)
- dimColor prop from AnnotationLayer

Simplified:
- AnnotationLayer: only canDraw + color + onDraw + onAnnotationClick
- PdfViewer: only draws in transcribeMode with turquoise
- Clicking annotation in transcribe mode scrolls to corresponding block
- canComment derived from canWrite (no longer needs canAnnotate)

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

frontend/src/lib/components/DocumentTopBar.svelte

@@ -4,7 +4,6 @@ import { slide } from 'svelte/transition';
 import { formatDate } from '$lib/utils/personFormat';
 import { clickOutside } from '$lib/actions/clickOutside';
 import PersonChipRow from './PersonChipRow.svelte';
-import AnnotateHintStrip from './AnnotateHintStrip.svelte';
 import OverflowPillButton from './OverflowPillButton.svelte';
 import DocumentMetadataDrawer from './DocumentMetadataDrawer.svelte';
 
@@ -28,20 +27,11 @@ type Doc = {
 type Props = {
 	doc: Doc;
 	canWrite: boolean;
-	canAnnotate: boolean;
 	fileUrl: string;
-	annotateMode: boolean;
 	transcribeMode: boolean;
 };
 
-let {
-	doc,
-	canWrite,
-	canAnnotate,
-	fileUrl,
-	annotateMode = $bindable(),
-	transcribeMode = $bindable()
-}: Props = $props();
+let { doc, canWrite, fileUrl, transcribeMode = $bindable() }: Props = $props();
 
 let detailsOpen = $state(false);
 
@@ -56,55 +46,10 @@ const longDate = $derived(doc.documentDate ? formatDate(doc.documentDate, 'long'
 let mobileMenuOpen = $state(false);
 </script>
 
-{#snippet annotateBtn(mobile: boolean)}
-	<button
-		onclick={() => {
-			annotateMode = true;
-			if (mobile) mobileMenuOpen = false;
-		}}
-		aria-label={m.doc_panel_annotate()}
-		aria-pressed={false}
-		class={mobile
-			? 'flex w-full items-center gap-2 rounded px-3 py-2 text-left text-[16px] text-ink transition hover:bg-muted focus-visible:ring-2 focus-visible:ring-primary'
-			: 'hidden items-center gap-1.5 rounded border border-primary px-3 py-1.5 font-sans text-[16px] font-medium text-ink transition hover:bg-primary hover:text-primary-fg focus-visible:ring-2 focus-visible:ring-primary md:flex'}
-	>
-		<img
-			src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Note/Note-Add-MD.svg"
-			alt=""
-			aria-hidden="true"
-			class="h-5 w-5 shrink-0"
-		/>
-		{m.doc_panel_annotate()}
-	</button>
-{/snippet}
-
-{#snippet annotateStopBtn(mobile: boolean)}
-	<button
-		onclick={() => {
-			annotateMode = false;
-			if (mobile) mobileMenuOpen = false;
-		}}
-		aria-label={m.doc_panel_annotate_stop()}
-		aria-pressed={true}
-		class={mobile
-			? 'flex w-full items-center gap-2 rounded bg-primary px-3 py-2 text-left text-[16px] text-primary-fg transition focus-visible:ring-2 focus-visible:ring-primary'
-			: 'flex items-center gap-1.5 rounded bg-primary px-3 py-1.5 font-sans text-[16px] font-medium text-primary-fg transition focus-visible:ring-2 focus-visible:ring-primary'}
-	>
-		<img
-			src="/degruyter-icons/Simple/Medium-24px/SVG/Action/Note/Note-Add-MD.svg"
-			alt=""
-			aria-hidden="true"
-			class="h-5 w-5 shrink-0 invert"
-		/>
-		{m.doc_panel_annotate_stop()}
-	</button>
-{/snippet}
-
 {#snippet transcribeBtn(mobile: boolean)}
 	<button
 		onclick={() => {
 			transcribeMode = true;
-			annotateMode = false;
 			if (mobile) mobileMenuOpen = false;
 		}}
 		aria-label={m.transcription_mode_label()}
@@ -256,7 +201,7 @@ let mobileMenuOpen = $state(false);
 
 		<!-- Action buttons -->
 		<div class="flex shrink-0 items-center gap-1.5 pr-3 font-sans">
-			{#if canWrite && isPdf && !transcribeMode && !annotateMode}
+			{#if canWrite && isPdf && !transcribeMode}
 				{@render transcribeBtn(false)}
 			{/if}
 
@@ -264,15 +209,7 @@ let mobileMenuOpen = $state(false);
 				{@render transcribeStopBtn(false)}
 			{/if}
 
-			{#if canAnnotate && isPdf && !annotateMode && !transcribeMode}
-				{@render annotateBtn(false)}
-			{/if}
-
-			{#if canAnnotate && isPdf && annotateMode}
-				{@render annotateStopBtn(false)}
-			{/if}
-
-			{#if canWrite && !annotateMode && !transcribeMode}
+			{#if canWrite && !transcribeMode}
 				<a
 					href="/documents/{doc.id}/edit"
 					aria-label={m.btn_edit()}
@@ -288,12 +225,12 @@ let mobileMenuOpen = $state(false);
 				</a>
 			{/if}
 
-			{#if doc.filePath && !annotateMode}
+			{#if doc.filePath && !transcribeMode}
 				{@render downloadLink(false)}
 			{/if}
 
 			<!-- Kebab menu — mobile only, contains actions hidden below md -->
-			{#if (canAnnotate && isPdf) || doc.filePath}
+			{#if (canWrite && isPdf) || doc.filePath}
 				<div
 					role="group"
 					class="relative md:hidden"
@@ -321,14 +258,10 @@ let mobileMenuOpen = $state(false);
 							role="menu"
 							class="absolute top-full right-0 z-50 mt-1 min-w-[200px] rounded-md border border-line bg-surface p-2 shadow-lg"
 						>
-							{#if canWrite && isPdf && !transcribeMode && !annotateMode}
+							{#if canWrite && isPdf && !transcribeMode}
 								{@render transcribeBtn(true)}
 							{/if}
 
-							{#if canAnnotate && isPdf && !annotateMode && !transcribeMode}
-								{@render annotateBtn(true)}
-							{/if}
-
 							{#if doc.filePath}
 								{@render downloadLink(true)}
 							{/if}
@@ -339,9 +272,6 @@ let mobileMenuOpen = $state(false);
 		</div>
 	</div>
 
-	<!-- Hint strip — only when annotateMode, only at ≥768px -->
-	<AnnotateHintStrip annotateMode={annotateMode} />
-
 	<!-- Metadata drawer -->
 	{#if detailsOpen}
 		<div transition:slide={{ duration: 200 }}>