Use minimal valid golangci-lint v2 configuration

Remove unsupported v2 schema elements:
- Remove linters-settings (not allowed at root level in v2)
- Remove issues.exclude-rules (not allowed in v2)
- Keep only core configuration that validates against v2 schema

This should finally pass the config verification.

Author: vnykmshr

.golangci.yml

@@ -2,78 +2,18 @@ version: "2"
 
 run:
   timeout: 5m
-  modules-download-mode: readonly
 
 linters:
   default: standard
   disable:
-    # Disable overly strict linters for this project
-    - varnamelen # Too strict for our use case
-    - wsl        # Too opinionated about whitespace
+    - varnamelen
+    - wsl
   enable:
-    # Add some useful additional linters
     - goconst
     - gocyclo
     - gosec
     - misspell
-    - unconvert
-    - unparam
-
-linters-settings:
-  errcheck:
-    check-type-assertions: true
-    check-blank: true
-
-  govet:
-    check-shadowing: true
-
-  gocyclo:
-    min-complexity: 15
-
-  goconst:
-    min-len: 2
-    min-occurrences: 2
-
-  gosec:
-    excludes:
-      - G404 # Use of weak random number generator is acceptable for cache keys
 
 issues:
-  exclude-rules:
-    # Test files are allowed to be less strict
-    - path: _test\.go
-      linters:
-        - gosec
-        - errcheck
-        - goconst
-        - unparam
-        - gocyclo
-
-    # Benchmark files focus on performance
-    - path: bench_test\.go
-      linters:
-        - errcheck
-        - unparam
-
-    # Example files can be less strict
-    - path: examples/
-      linters:
-        - gosec
-
-    # Reflection code needs some flexibility
-    - path: pkg/obcache/wrap\.go
-      linters:
-        - errcheck
-
-    # Allow string keys in context for testing
-    - text: "should not use built-in type string as key"
-      linters:
-        - staticcheck
-
-    # Allow empty branches in example code
-    - text: "empty branch"
-      linters:
-        - staticcheck
-
   max-issues-per-linter: 0
   max-same-issues: 0