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/math-intrinsics/isNegativeZero.js

@@ -0,0 +1,6 @@
+'use strict';
+
+/** @type {import('./isNegativeZero')} */
+module.exports = function isNegativeZero(x) {
+	return x === 0 && 1 / x === 1 / -0;
+};