fix: replace fmt.Errorf with signoz/pkg/errors and update golangci-li… (#9373)

This PR fulfills the requirements of #9069 by:

- Adding a golangci-lint directive (forbidigo) to disallow all fmt.Errorf usages.
- Replacing existing fmt.Errorf instances with structured errors from github.com/SigNoz/signoz/pkg/errors for consistent error classification and lint compliance.
- Verified lint and build integrity.

.golangci.yml

@@ -32,6 +32,10 @@ linters-settings:
   iface:
     enable:
       - identical
+  forbidigo:
+    forbid:
+      - fmt.Errorf
+      - ^(fmt\.Print.*|print|println)$
 issues:
   exclude-dirs:
     - "pkg/query-service"