Fix errcheck lint failures in CI

golangci-lint errcheck flagged six unchecked error returns, failing the
pr/test workflow's lint step and skipping tests.

- Blank-assign hash writes in Row.Key and MarkHidden calls
- Close response body via deferred func matching node-lookup convention
- Read test request body with io.ReadAll instead of a single Body.Read

internal/chlog/client.go

@@ -42,7 +42,7 @@ func (r Row) Time() time.Time {
 func (r Row) Key() uint64 {
 	h := fnv.New64a()
 	for _, s := range []string{r.Timestamp, r.Host, r.Source, r.Namespace, r.Pod, r.Container, r.Stream, r.Message} {
-		io.WriteString(h, s)
+		_, _ = io.WriteString(h, s)
 		h.Write([]byte{0})
 	}
 	return h.Sum64()
@@ -81,7 +81,7 @@ func (c *Client) Run(ctx context.Context, q Query, fn func(Row) error) error {
 	if err != nil {
 		return fmt.Errorf("clickhouse request: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		body, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))

internal/chlog/client_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"strconv"
@@ -54,8 +55,7 @@ func (f *fakeCH) handler(t *testing.T) http.HandlerFunc {
 		f.queries++
 		f.lastUser = r.Header.Get("X-ClickHouse-User")
 		f.lastPass = r.Header.Get("X-ClickHouse-Key")
-		body := make([]byte, r.ContentLength)
-		r.Body.Read(body)
+		body, _ := io.ReadAll(r.Body)
 		f.lastSQL = string(body)
 
 		q := r.URL.Query()
@@ -80,7 +80,7 @@ func (f *fakeCH) handler(t *testing.T) http.HandlerFunc {
 			if limit >= 0 && sent >= limit {
 				break
 			}
-			enc.Encode(row)
+			_ = enc.Encode(row)
 			sent++
 		}
 	}

main.go

@@ -141,8 +141,8 @@ func newTailCmd(use string) *cobra.Command {
 		},
 	}
 	cf.register(cmd, 0)
-	cmd.Flags().MarkHidden("until")
-	cmd.Flags().MarkHidden("limit")
+	_ = cmd.Flags().MarkHidden("until")
+	_ = cmd.Flags().MarkHidden("limit")
 	return cmd
 }