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/postcss/lib/stringify.d.ts

@@ -0,0 +1,9 @@
+import { Stringifier } from './postcss.js'
+
+interface Stringify extends Stringifier {
+  default: Stringify
+}
+
+declare const stringify: Stringify
+
+export = stringify