feat: robust metric extraction with confidence score and proof snippets

- fixed Year-Prefix Bug in MetricParser
- added metric_confidence and metric_proof_text to database
- added Entity-Check and Annual-Priority to LLM prompt
- improved UI: added confidence traffic light and mouse-over proof tooltip
- restored missing API endpoints (create, bulk, wiki-override)

company-explorer/frontend/node_modules/axios/lib/helpers/combineURLs.js

@@ -0,0 +1,15 @@
+'use strict';
+
+/**
+ * Creates a new URL by combining the specified URLs
+ *
+ * @param {string} baseURL The base URL
+ * @param {string} relativeURL The relative URL
+ *
+ * @returns {string} The combined URL
+ */
+export default function combineURLs(baseURL, relativeURL) {
+  return relativeURL
+    ? baseURL.replace(/\/?\/$/, '') + '/' + relativeURL.replace(/^\/+/, '')
+    : baseURL;
+}