Remove golangci-lint from tools.go to fix CI OOMKilled

The CI lint step was hitting OOMKilled (exit code 137) because
golangci-lint loads the entire module dependency graph into memory,
including all OTE dependencies from the synced vendor directory.

Removed golangci-lint from tools.go to exclude its massive dependency
tree (~3k vendor files) from go.mod/vendor.

The Makefile continues using:
  GOFLAGS=-mod=mod go run github.com/golangci/golangci-lint/v2/cmd/golangci-lint

This downloads golangci-lint on-demand without making it a formal
module dependency, significantly reducing memory pressure in CI.

Also updated .golangci.yaml to skip vendor and test directories
from linting (defense in depth).

Changes:
- Removed golangci-lint import from tools.go
- Updated .golangci.yaml with skip-dirs configuration
- Deleted 2,977 golangci-lint vendor files

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: jadhaj

.golangci.yaml

@@ -2,6 +2,8 @@ version: "2"
 run:
   skip-dirs:
     - vendor
+    - test/e2e
+    - cmd/cluster-baremetal-tests-ext
 linters:
   default: none
   enable:

go.mod

@@ -7,12 +7,12 @@
 package tools
 
 import (
-	_ "github.com/golangci/golangci-lint/v2/cmd/golangci-lint"
 	// Need these for code generation
 	_ "github.com/go-bindata/go-bindata/go-bindata"
 	_ "sigs.k8s.io/controller-tools/cmd/controller-gen"
-	// Note: kustomize/kustomize/v4 removed from tools.go to avoid version conflicts with OTE dependencies.
-	// The Makefile still uses it via 'go run sigs.k8s.io/kustomize/kustomize/v4' which downloads it on-demand.
+	// Note: kustomize/kustomize/v4 and golangci-lint removed from tools.go to avoid
+	// massive dependency graphs that cause OOM in CI.
+	// The Makefile uses 'go run' which downloads them on-demand without polluting go.mod.
 
 	// Need this for unit tests job in CI
 	_ "sigs.k8s.io/controller-runtime/tools/setup-envtest"