feat(cli): colorized, columnized text output with line:col locations

Replace the per-line fmt.Println loop with writeTextFindings() in
cmd/glint/output.go. The new renderer:

- Aligns all findings into four space-separated columns: location,
  rule ID, severity, message — widths computed from the full finding
  set so all lines are flush
- Colors severity words when stdout is a TTY and NO_COLOR is not set:
  red+bold for "error", orange+bold for "warning"; location dimmed;
  rule ID bold
- Formats location as file:line:col when column is known, file:line
  otherwise, falling back to just file

To populate column numbers, add Column int to model.Job (set from
keyNode.Column in the YAML parser) and Finding.Column (set during
the checkJob source-location attachment pass and in the ten cross-job
check sites that explicitly set Line: job.Line).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/linter/linter.go

@@ -22,15 +22,19 @@ type Finding struct {
 	Job      string // empty for pipeline-level findings
 	File     string // source file where the finding originates
 	Line     int    // line number in File (0 = unknown)
+	Column   int    // column number in File (0 = unknown; 1-indexed)
 	Message  string
 }
 
 func (f Finding) String() string {
 	var loc string
 	if f.File != "" {
-		if f.Line > 0 {
+		switch {
+		case f.Line > 0 && f.Column > 0:
+			loc = fmt.Sprintf("%s:%d:%d: ", f.File, f.Line, f.Column)
+		case f.Line > 0:
 			loc = fmt.Sprintf("%s:%d: ", f.File, f.Line)
-		} else {
+		default:
 			loc = fmt.Sprintf("%s: ", f.File)
 		}
 	}
@@ -225,6 +229,7 @@ func checkJob(name string, job model.Job, stageSet map[string]bool) []Finding {
 		if findings[i].Job != "" && findings[i].File == "" {
 			findings[i].File = job.File
 			findings[i].Line = job.Line
+			findings[i].Column = job.Column
 		}
 	}
 	return findings