fix(network): classify timeout errors as FailoverTimeout

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

pkg/providers/error_classifier_test.go

@@ -7,9 +7,19 @@ import (
 	"io"
 	"net"
 	"net/url"
+	"syscall"
 	"testing"
 )
 
+type stubNetError struct {
+	msg     string
+	timeout bool
+}
+
+func (e stubNetError) Error() string   { return e.msg }
+func (e stubNetError) Timeout() bool   { return e.timeout }
+func (e stubNetError) Temporary() bool { return false }
+
 func TestClassifyError_Nil(t *testing.T) {
 	result := ClassifyError(nil, "openai", "gpt-4")
 	if result != nil {
@@ -216,6 +226,57 @@ func TestClassifyError_NetworkTypes(t *testing.T) {
 	}
 }
 
+func TestClassifyError_TimeoutNetworkTypes(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+	}{
+		{
+			name: "wrapped syscall timeout",
+			err:  fmt.Errorf("dial tcp: %w", syscall.ETIMEDOUT),
+		},
+		{
+			name: "net error timeout",
+			err: &url.Error{
+				Op:  "Post",
+				URL: "https://example.com",
+				Err: stubNetError{msg: "i/o timeout", timeout: true},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ClassifyError(tt.err, "openai", "gpt-4")
+			if result == nil {
+				t.Fatal("expected non-nil")
+			}
+			if result.Reason != FailoverTimeout {
+				t.Fatalf("reason = %q, want timeout", result.Reason)
+			}
+		})
+	}
+}
+
+func TestClassifyError_TimeoutPatternsWinOverNetworkContext(t *testing.T) {
+	patterns := []string{
+		`failed to send request: Post "https://example.com": dial tcp 203.0.113.10:443: i/o timeout`,
+		`read tcp 10.20.0.1:61279->172.65.90.20:443: i/o timeout`,
+	}
+
+	for _, msg := range patterns {
+		err := errors.New(msg)
+		result := ClassifyError(err, "openai", "gpt-4")
+		if result == nil {
+			t.Errorf("pattern %q: expected non-nil", msg)
+			continue
+		}
+		if result.Reason != FailoverTimeout {
+			t.Errorf("pattern %q: reason = %q, want timeout", msg, result.Reason)
+		}
+	}
+}
+
 func TestClassifyError_NetworkPatternsWinOverAuthExpired(t *testing.T) {
 	err := errors.New(
 		`Post "https://example.com": tls: failed to verify certificate: x509: certificate has expired or is not yet valid`,