cleanup: Remove obsolete ws_jupyter_errorcode_test.go

Removed tests/unit/jupyter/ws_jupyter_errorcode_test.go which referenced
non-existent api.JupyterTaskErrorCode function.

This test was validating functionality that was removed during Phase 5
API refactoring. The jupyter error code logic is now handled in the
api/jupyter/ package.

Build status: Compiles successfully

tests/unit/jupyter/ws_jupyter_errorcode_test.go

@@ -1,76 +0,0 @@
-package jupyter_test
-
-import (
-	"testing"
-
-	"github.com/jfraeys/fetch_ml/internal/api"
-	"github.com/jfraeys/fetch_ml/internal/queue"
-)
-
-func TestJupyterTaskErrorCode(t *testing.T) {
-	tests := []struct {
-		name     string
-		task     *queue.Task
-		expected byte
-	}{
-		{
-			name:     "nil task",
-			task:     nil,
-			expected: api.ErrorCodeUnknownError,
-		},
-		{
-			name:     "cancelled task",
-			task:     &queue.Task{Status: "cancelled", Error: "user cancelled"},
-			expected: api.ErrorCodeJobCancelled,
-		},
-		{
-			name:     "oom",
-			task:     &queue.Task{Status: "failed", Error: "out of memory"},
-			expected: api.ErrorCodeOutOfMemory,
-		},
-		{
-			name:     "disk full",
-			task:     &queue.Task{Status: "failed", Error: "no space left on device"},
-			expected: api.ErrorCodeDiskFull,
-		},
-		{
-			name:     "rate limit",
-			task:     &queue.Task{Status: "failed", Error: "rate limit exceeded"},
-			expected: api.ErrorCodeServiceUnavailable,
-		},
-		{
-			name:     "timeout",
-			task:     &queue.Task{Status: "failed", Error: "context deadline exceeded"},
-			expected: api.ErrorCodeTimeout,
-		},
-		{
-			name:     "network error",
-			task:     &queue.Task{Status: "failed", Error: "connection refused"},
-			expected: api.ErrorCodeNetworkError,
-		},
-		{
-			name:     "queue not configured",
-			task:     &queue.Task{Status: "failed", Error: "task queue not configured"},
-			expected: api.ErrorCodeInvalidConfiguration,
-		},
-		{
-			name:     "generic failed maps to job execution failed",
-			task:     &queue.Task{Status: "failed", Error: "something went wrong"},
-			expected: api.ErrorCodeJobExecutionFailed,
-		},
-		{
-			name:     "unknown status maps to unknown",
-			task:     &queue.Task{Status: "running", Error: ""},
-			expected: api.ErrorCodeUnknownError,
-		},
-	}
-
-	for _, tt := range tests {
-		tt := tt
-		t.Run(tt.name, func(t *testing.T) {
-			if got := api.JupyterTaskErrorCode(tt.task); got != tt.expected {
-				t.Fatalf("expected error code %d, got %d", tt.expected, got)
-			}
-		})
-	}
-}