Enable Wellfound apply: fix missing apply_type, add submit verification

- Search now sets apply_type: 'wellfound' on discovered jobs (was missing,
  so applier silently skipped all Wellfound jobs)
- Add Wellfound to DEFAULT_ENABLED_APPLY_TYPES (LinkedIn first, then Wellfound)
- Sort platform processing order: linkedin → wellfound → external
- Apply handler: add closed listing detection, submit verification,
  error handling on meta extraction

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

lib/apply/wellfound.mjs

@@ -14,7 +14,18 @@ export async function apply(page, job, formFiller) {
   const meta = await page.evaluate(() => ({
     title: document.querySelector('h1')?.textContent?.trim(),
     company: document.querySelector('[class*="company"] h2, [class*="startup"] h2, h2')?.textContent?.trim(),
-  }));
+  })).catch(() => ({}));
+
+  // Check if listing is closed/unavailable
+  const closed = await page.evaluate(() => {
+    const text = (document.body.innerText || '').toLowerCase();
+    return text.includes('no longer accepting') || text.includes('position has been filled') ||
+           text.includes('this job is no longer') || text.includes('job not found');
+  }).catch(() => false);
+  if (closed) {
+    console.log(`    ℹ️  Job closed — no longer available`);
+    return { status: 'skipped_no_apply', meta };
+  }
 
   const applyBtn = page.locator('a:has-text("Apply"), button:has-text("Apply Now"), a:has-text("Apply Now")').first();
   if (await applyBtn.count() === 0) return { status: 'no_button', meta };
@@ -33,5 +44,20 @@ export async function apply(page, job, formFiller) {
   await submitBtn.click();
   await page.waitForTimeout(SUBMIT_WAIT);
 
-  return { status: 'submitted', meta };
+  // Verify submission — check for success indicators or form gone
+  const postSubmit = await page.evaluate(() => {
+    const text = (document.body.innerText || '').toLowerCase();
+    return {
+      hasSuccess: text.includes('application submitted') || text.includes('successfully applied') ||
+                  text.includes('thank you') || text.includes('application received'),
+      hasForm: !!document.querySelector('form button[type="submit"]:not([disabled])'),
+    };
+  }).catch(() => ({ hasSuccess: false, hasForm: false }));
+
+  if (postSubmit.hasSuccess || !postSubmit.hasForm) {
+    return { status: 'submitted', meta };
+  }
+
+  console.log(`    ⚠️  Submit clicked but form still present — may not have submitted`);
+  return { status: 'incomplete', meta };
 }