Initial Context Extractor: extension + Playwright/Camoufox package

Ship a shared markdown/prompt core used by a Brave/Chrome MV3 extension and a Python automation API, with pytest coverage, CI, and packaging smoke.

extension/background.js

@@ -0,0 +1,18 @@
+// background.js — Context Extractor service worker
+// Persists the selector chosen via the in-page element picker so the popup
+// can pre-fill it the next time it opens.
+
+chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
+  if (!msg || !msg.type) return false;
+
+  if (msg.type === "PICKER_SELECTED") {
+    const selector = msg.selector || "";
+    chrome.storage.session
+      .set({ pickerSelector: selector })
+      .then(() => sendResponse({ ok: true }))
+      .catch((err) => sendResponse({ ok: false, error: String(err) }));
+    return true; // async response
+  }
+
+  return false;
+});