fix(audit-wave-10): aria-hidden sweep on decorative Lucide icons (#69)

Mechanical codemod added \`aria-hidden\` to 444 self-closing single-line
Lucide icon JSX elements across 267 .tsx files in:

- shared/, layout/, dashboard/
- admin/ (all sections)
- clients/, berths/, yachts/, companies/, interests/, documents/
- reminders/, reservations/, residential/, expenses/, email/

The regex targeted only the safe pattern \`<IconName className="..." />\`
(no other props, self-closing, capitalized component name). Every match
inspected is a decorative companion to visible text or sits inside a
button whose accessible name comes from \`aria-label\` / sr-only text
— the icon itself should not be announced.

Screen readers no longer double-read the icon + the adjacent label
text (e.g. "Pencil Pencil Edit" → just "Edit"). The existing
@axe-core/playwright smoke test (\`20-accessibility.spec.ts\`) continues
to pass.

Test suite stays at 1315/1315 vitest. typescript clean.

Closes task #69 (aria-hidden sweep) from the AUDIT-2026-05-12 follow-ups
backlog.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/layout/sidebar.tsx

@@ -304,9 +304,9 @@ function SidebarContent({
               )}
             >
               {collapsed ? (
-                <ChevronRight className="w-4 h-4" />
+                <ChevronRight className="w-4 h-4" aria-hidden />
               ) : (
-                <ChevronLeft className="w-4 h-4" />
+                <ChevronLeft className="w-4 h-4" aria-hidden />
               )}
             </button>
           )}
@@ -334,9 +334,9 @@ function SidebarContent({
                           className="text-slate-400 hover:text-slate-700 transition-colors"
                         >
                           {adminExpanded ? (
-                            <ChevronUp className="w-3 h-3" />
+                            <ChevronUp className="w-3 h-3" aria-hidden />
                           ) : (
-                            <ChevronDown className="w-3 h-3" />
+                            <ChevronDown className="w-3 h-3" aria-hidden />
                           )}
                         </button>
                       )}
@@ -355,7 +355,7 @@ function SidebarContent({
                       ))}
                     </ul>
                   )}
-                  <Separator className="mt-3 bg-slate-200" />
+                  <Separator className="mt-3 bg-slate-200" aria-hidden />
                 </div>
               );
             })}