fix: cover letter silent drop, submit verification, autocomplete scoping

- Text inputs matched to cover letter now report as unknown if required,
  instead of silently leaving the field empty
- Submit click now verifies modal closed before reporting success;
  returns 'incomplete' with actionable log if modal stays open
- selectAutocomplete scoped to container (modal) to avoid clicking
  wrong dropdowns from the underlying page

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

lib/apply/easy_apply.mjs

@@ -207,7 +207,20 @@ export async function apply(page, job, formFiller) {
       console.log(`    [step ${step}] clicking Submit`);
       await submitBtn.click({ timeout: APPLY_CLICK_TIMEOUT }).catch(() => {});
       await page.waitForTimeout(SUBMIT_WAIT);
-      return { status: 'submitted', meta };
+
+      // Verify modal closed or success message appeared
+      const modalGone = !(await page.$(MODAL));
+      const successVisible = await page.$('[class*="success"], [class*="confirmation"], [aria-label*="applied"]').catch(() => null);
+      if (modalGone || successVisible) {
+        console.log(`    ✅ Submit confirmed — modal closed`);
+        return { status: 'submitted', meta };
+      }
+
+      // Modal still open — submit may have failed
+      console.log(`    [step ${step}] ⚠️  Modal still open after Submit click`);
+      console.log(`    Action: submit may have failed due to validation or network error`);
+      await dismissModal(page, MODAL);
+      return { status: 'incomplete', meta };
     }
 
     // Stuck detection — progress hasn't changed and we've been through a few steps