Classify unknown_external jobs by following Apply redirects

After LinkedIn search completes, visits each unknown_external job page,
clicks the Apply button, captures the redirect URL, and matches against
known ATS patterns to identify the actual application platform.

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

lib/linkedin.mjs

@@ -143,3 +143,66 @@ export async function searchLinkedIn(page, search, { onPage, onKeyword } = {}) {
 
   return jobs;
 }
+
+/**
+ * Classify unknown_external jobs by following the Apply button redirect.
+ * Visits each job page, clicks Apply, captures the redirect URL, and
+ * matches against known ATS patterns.
+ *
+ * @param {Page} page — authenticated LinkedIn browser page
+ * @param {Array} jobs — jobs with apply_type 'unknown_external'
+ * @param {Function} onClassified — callback(job, apply_type, apply_url) for each classified job
+ * @returns {{ classified: number, remaining: number }}
+ */
+export async function classifyExternalJobs(page, jobs, onClassified) {
+  let classified = 0;
+  let remaining = 0;
+
+  for (const job of jobs) {
+    const url = job.url || job.apply_url;
+    if (!url) { remaining++; continue; }
+
+    try {
+      await page.goto(url, { waitUntil: 'domcontentloaded', timeout: NAVIGATION_TIMEOUT });
+      await page.waitForTimeout(2000);
+
+      // Click the Apply button and catch the new tab
+      const applyBtn = await page.$('button.jobs-apply-button:not([aria-label*="Easy Apply"])')
+        || await page.$('a.jobs-apply-button');
+      if (!applyBtn) { remaining++; continue; }
+
+      const [newPage] = await Promise.all([
+        page.context().waitForEvent('page', { timeout: 8000 }).catch(() => null),
+        applyBtn.click(),
+      ]);
+
+      let externalUrl = null;
+      if (newPage) {
+        await newPage.waitForLoadState('domcontentloaded', { timeout: 8000 }).catch(() => {});
+        externalUrl = newPage.url();
+        await newPage.close().catch(() => {});
+      }
+
+      if (!externalUrl || externalUrl.includes('linkedin.com')) {
+        remaining++;
+        continue;
+      }
+
+      // Match against ATS patterns
+      let applyType = 'unknown_external';
+      for (const { name, pattern } of EXTERNAL_ATS_PATTERNS) {
+        if (pattern.test(externalUrl)) {
+          applyType = name;
+          break;
+        }
+      }
+
+      onClassified(job, applyType, externalUrl);
+      classified++;
+    } catch {
+      remaining++;
+    }
+  }
+
+  return { classified, remaining };
+}