Add chlog CLI with chcat/chtail/chgrep entrypoints

Single Go binary for the ClickHouse log store (logs.raw): chlog with
cat/tail/grep subcommands, plus chcat/chtail/chgrep argv[0]-dispatched
symlink entrypoints. Every query is time-bounded and fully parameterized;
chgrep guards wide unfiltered scans. Ships nfpm RPM with completions and
woodpecker PR/tag pipelines mirroring node-lookup.

internal/chlog/format.go

@@ -0,0 +1,149 @@
+package chlog
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+)
+
+const (
+	colReset = "\x1b[0m"
+	colDim   = "\x1b[2m"
+	colCyan  = "\x1b[36m"
+	colGreen = "\x1b[32m"
+	colRed   = "\x1b[31m"
+	colYel   = "\x1b[33m"
+)
+
+type Formatter func(w io.Writer, r Row) error
+
+func NewFormatter(format string, color bool) (Formatter, error) {
+	switch format {
+	case "text":
+		return textFormatter(color), nil
+	case "json":
+		return jsonFormatter, nil
+	case "logfmt":
+		return logfmtFormatter, nil
+	default:
+		return nil, fmt.Errorf("unknown format %q: want text, json or logfmt", format)
+	}
+}
+
+// origin renders the row's source identity: ns/pod for k8s rows, host for vm.
+func origin(r Row) string {
+	if r.Pod != "" {
+		return r.Namespace + "/" + r.Pod
+	}
+	if r.Namespace != "" {
+		return r.Namespace
+	}
+	return r.Host
+}
+
+func severityColor(sev string) string {
+	switch strings.ToLower(sev) {
+	case "error", "err", "fatal", "critical", "crit":
+		return colRed
+	case "warn", "warning":
+		return colYel
+	default:
+		return ""
+	}
+}
+
+func textFormatter(color bool) Formatter {
+	return func(w io.Writer, r Row) error {
+		ts := r.Time().Format("2006-01-02T15:04:05.000Z")
+		msg := r.Message
+		if !color {
+			_, err := fmt.Fprintf(w, "%s %s %s\n", ts, origin(r), msg)
+			return err
+		}
+		if c := severityColor(r.Severity); c != "" {
+			msg = c + msg + colReset
+		}
+		_, err := fmt.Fprintf(w, "%s%s%s %s%s%s %s\n",
+			colDim, ts, colReset, colCyan, origin(r), colReset, msg)
+		return err
+	}
+}
+
+type jsonRow struct {
+	Timestamp string            `json:"timestamp"`
+	Host      string            `json:"host"`
+	Source    string            `json:"source"`
+	Namespace string            `json:"namespace,omitempty"`
+	Pod       string            `json:"pod,omitempty"`
+	Container string            `json:"container,omitempty"`
+	Stream    string            `json:"stream,omitempty"`
+	Severity  string            `json:"severity,omitempty"`
+	Message   string            `json:"message"`
+	Labels    map[string]string `json:"labels,omitempty"`
+	Fields    map[string]string `json:"fields,omitempty"`
+}
+
+func jsonFormatter(w io.Writer, r Row) error {
+	b, err := json.Marshal(jsonRow{
+		Timestamp: r.Time().Format(time.RFC3339Nano),
+		Host:      r.Host,
+		Source:    r.Source,
+		Namespace: r.Namespace,
+		Pod:       r.Pod,
+		Container: r.Container,
+		Stream:    r.Stream,
+		Severity:  r.Severity,
+		Message:   r.Message,
+		Labels:    r.Labels,
+		Fields:    r.Fields,
+	})
+	if err != nil {
+		return err
+	}
+	_, err = fmt.Fprintf(w, "%s\n", b)
+	return err
+}
+
+func logfmtValue(s string) string {
+	if s == "" {
+		return `""`
+	}
+	if strings.ContainsAny(s, " \t\"=\n") {
+		return fmt.Sprintf("%q", s)
+	}
+	return s
+}
+
+func logfmtFormatter(w io.Writer, r Row) error {
+	var b strings.Builder
+	pair := func(k, v string) {
+		if v == "" {
+			return
+		}
+		if b.Len() > 0 {
+			b.WriteByte(' ')
+		}
+		b.WriteString(k)
+		b.WriteByte('=')
+		b.WriteString(logfmtValue(v))
+	}
+	pair("ts", r.Time().Format(time.RFC3339Nano))
+	pair("source", r.Source)
+	pair("host", r.Host)
+	pair("ns", r.Namespace)
+	pair("pod", r.Pod)
+	pair("container", r.Container)
+	pair("stream", r.Stream)
+	pair("severity", r.Severity)
+	pair("app", r.Labels["app"])
+	if b.Len() > 0 {
+		b.WriteByte(' ')
+	}
+	b.WriteString("msg=")
+	b.WriteString(logfmtValue(r.Message))
+	b.WriteByte('\n')
+	_, err := io.WriteString(w, b.String())
+	return err
+}