fix radio button state not updating in new job form

The setValueAs transformation wasn't working correctly with radio
buttons in react-hook-form, causing the form value to remain a string
instead of being converted to a boolean. This caused Zod validation
to fail silently since the schema expects a boolean.

Fixed by using controlled radio buttons with explicit onChange handlers
that call setValue() with the proper boolean value.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/routes/jobs/NewJob.tsx

@@ -245,8 +245,9 @@ export function NewJob() {
             <label className="flex items-center">
               <input
                 type="radio"
-                {...register('sourceIsEnglish', { setValueAs: (v) => v === 'true' || v === true })}
-                value="true"
+                name="sourceIsEnglish"
+                checked={sourceIsEnglish === true}
+                onChange={() => setValue('sourceIsEnglish', true)}
                 className="mr-2"
               />
               <span>English</span>
@@ -254,8 +255,9 @@ export function NewJob() {
             <label className="flex items-center">
               <input
                 type="radio"
-                {...register('sourceIsEnglish', { setValueAs: (v) => v === 'true' || v === true })}
-                value="false"
+                name="sourceIsEnglish"
+                checked={sourceIsEnglish === false}
+                onChange={() => setValue('sourceIsEnglish', false)}
                 className="mr-2"
               />
               <span>Different language (auto-detect)</span>