feat: Per-section change indicators in title TOC

apps/web/src/pages/browse/[title].astro

@@ -27,6 +27,24 @@ export async function getStaticPaths() {
 const { titleNum, entries } = Astro.props;
 const titleName = TITLE_NAMES[titleNum] ?? `Title ${titleNum}`;
 
+// Load per-section change index (generated by generate-diffs.ts)
+let changedSections: Record<string, string[]> = {};
+try {
+  const { readFile } = await import('node:fs/promises');
+  const { join } = await import('node:path');
+  const diffsDir = new URL('../../../public/diffs/', import.meta.url).pathname;
+  const raw = await readFile(join(diffsDir, 'changed-sections.json'), 'utf8');
+  changedSections = JSON.parse(raw) as Record<string, string[]>;
+} catch {
+  // No change data available yet
+}
+
+/** Check if a section was changed in any release point */
+function sectionChangedIn(section: string): string[] {
+  const key = `title-${titleNum}/${section}`;
+  return changedSections[key] ?? [];
+}
+
 // Group entries by chapter, sort sections within each chapter
 const byChapter = new Map<number, typeof entries>();
 for (const entry of entries) {
@@ -145,16 +163,23 @@ const autoExpand = sortedChapters.length <= 10;
                 sTitle.includes('Renumbered') ? 'Renumbered' :
                 sTitle.includes('Transferred') ? 'Transferred' : null
               );
+              const changes = sectionChangedIn(`section-${entry.data.usc_section}`);
+              const lastChange = changes.length > 0 ? changes[changes.length - 1] : null;
 
               return (
                 <li>
                   <a
                     href={`${base}statute/${entry.id}/`}
                     class:list={[
-                      'flex items-baseline gap-3 px-4 py-1.5 pl-12 text-xs transition-colors hover:bg-gray-50 dark:hover:bg-gray-900',
+                      'flex items-center gap-3 px-4 py-1.5 pl-12 text-xs transition-colors hover:bg-gray-50 dark:hover:bg-gray-900',
                       isInactive && 'opacity-50',
                     ]}
                   >
+                    {lastChange ? (
+                      <span class="h-1.5 w-1.5 shrink-0 rounded-full bg-teal" title={`Changed in ${lastChange.replace('pl-', 'PL ').replace('-', '-')}`} aria-label="Recently changed"></span>
+                    ) : (
+                      <span class="h-1.5 w-1.5 shrink-0"></span>
+                    )}
                     <span class="w-14 shrink-0 text-right font-mono text-[11px] text-slate dark:text-gray-500">
                       &sect; {entry.data.usc_section}
                     </span>
@@ -164,11 +189,15 @@ const autoExpand = sortedChapters.length <= 10;
                     ]}>
                       {sTitle.replace(/^Section \S+ - /, '')}
                     </span>
-                    {statusLabel && (
+                    {statusLabel ? (
                       <span class="ml-auto shrink-0 rounded bg-gray-100 px-1 py-0.5 text-[9px] font-medium text-gray-500 dark:bg-gray-800 dark:text-gray-500">
                         {statusLabel}
                       </span>
-                    )}
+                    ) : lastChange ? (
+                      <span class="ml-auto shrink-0 text-[9px] text-teal dark:text-teal-bright">
+                        {lastChange.replace('pl-', 'PL ').replace('-', '-')}
+                      </span>
+                    ) : null}
                   </a>
                 </li>
               );

scripts/generate-diffs.ts

@@ -12,7 +12,7 @@
  */
 
 import { execSync } from 'node:child_process';
-import { readFile, writeFile, mkdir } from 'node:fs/promises';
+import { readFile, readdir, writeFile, mkdir } from 'node:fs/promises';
 import { join } from 'node:path';
 import { parseArgs } from 'node:util';
 
@@ -198,6 +198,26 @@ manifest.pairs.sort((a, b) => {
   return ac !== bc ? ac - bc : al - bl;
 });
 
+// Build per-section change index: { "title-18/section-111": ["pl-117-159", ...] }
+const sectionChanges: Record<string, string[]> = {};
+for (const pair of manifest.pairs) {
+  const pairDir = join(output, `${pair.from}_${pair.to}`);
+  try {
+    const titles = await readdir(pairDir).catch(() => [] as string[]);
+    for (const titleDir of titles) {
+      const sections = await readdir(join(pairDir, titleDir)).catch(() => [] as string[]);
+      for (const sectionFile of sections) {
+        const key = `${titleDir}/${sectionFile.replace('.json', '')}`;
+        if (!sectionChanges[key]) sectionChanges[key] = [];
+        sectionChanges[key].push(pair.to);
+      }
+    }
+  } catch {
+    // Pair dir may not exist for cached entries from previous runs
+  }
+}
+
 await mkdir(output, { recursive: true });
 await writeFile(join(output, 'manifest.json'), JSON.stringify(manifest, null, 2));
-console.log(`Done. ${computed} new pairs computed, ${skipped} skipped (already cached). Manifest: ${output}/manifest.json`);
+await writeFile(join(output, 'changed-sections.json'), JSON.stringify(sectionChanges));
+console.log(`Done. ${computed} new pairs computed, ${skipped} skipped (already cached). ${Object.keys(sectionChanges).length} sections with changes tracked. Manifest: ${output}/manifest.json`);