fix(analyzer): multi-select option click swallowed by nested Radix button

Radix Checkbox renders as <button role="checkbox">, which we were nesting
inside the option <button>. Browsers can swallow the outer click in that
arrangement despite pointer-events-none on the inner element. Replaced the
option with <div role="option" tabIndex={0}> and an inline non-button
visual checkbox (square + Check icon when selected). Keyboard support
(Enter/Space) preserved.

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

components/ui/multi-select.tsx

@@ -8,9 +8,8 @@ import {
 } from '@/components/ui/popover';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
-import { Checkbox } from '@/components/ui/checkbox';
 import { Badge } from '@/components/ui/badge';
-import { ChevronDown, Search, X } from 'lucide-react';
+import { Check, ChevronDown, Search, X } from 'lucide-react';
 
 export interface MultiSelectOption {
   value: string;
@@ -127,15 +126,32 @@ export function MultiSelect({
             filtered.map((opt) => {
               const checked = valueSet.has(opt.value);
               return (
-                <button
+                <div
                   key={opt.value}
-                  type="button"
+                  role="option"
+                  aria-selected={checked}
+                  tabIndex={0}
                   onClick={() => toggle(opt.value)}
-                  className="flex items-center gap-2 w-full px-3 py-1.5 text-sm hover:bg-accent text-left"
+                  onKeyDown={(e) => {
+                    if (e.key === 'Enter' || e.key === ' ') {
+                      e.preventDefault();
+                      toggle(opt.value);
+                    }
+                  }}
+                  className="flex items-center gap-2 w-full px-3 py-1.5 text-sm hover:bg-accent cursor-pointer select-none focus:bg-accent focus:outline-none"
                 >
-                  <Checkbox checked={checked} className="pointer-events-none" />
+                  <span
+                    className={`w-4 h-4 shrink-0 rounded-sm border flex items-center justify-center transition ${
+                      checked
+                        ? 'bg-primary border-primary text-primary-foreground'
+                        : 'border-input bg-background'
+                    }`}
+                    aria-hidden="true"
+                  >
+                    {checked && <Check className="w-3 h-3" strokeWidth={3} />}
+                  </span>
                   <span className="truncate">{opt.label}</span>
-                </button>
+                </div>
               );
             })
           )}