fix: remove all unused code (#12360)

.golangci.yml

@@ -19,6 +19,9 @@ linters:
     - structcheck
     - gomodguard
     - gofmt
+    - unused
+    - structcheck
+    - unconvert
 
 issues:
   exclude-use-default: false
@@ -26,11 +29,5 @@ issues:
       - should have a package comment
       - error strings should not be capitalized or end with punctuation or a newline
 
-run:
-  skip-dirs:
-    - pkg/rpc
-    - pkg/argon2
-    - pkg/s3select/internal
-
 service:
   golangci-lint-version: 1.20.0 # use the fixed version to not introduce new linters unexpectedly