Logging: structured slog messages throughout, and WithLogger options so callers choose the logger

Log messages are lower-case event names with their details as key/value
attributes ("error" for errors), in place of formatted strings.

Loggable package take a WithLogger option as part of their "New*" call,
defaulting to slog.Default(). Each tags its lines with its `component`.

Some debug loggers print directly rather than using slog when in
terminal logging mode.

internal/cli/confirm_action.go

@@ -3,7 +3,7 @@ package cli
 import (
 	"bufio"
 	"fmt"
-	"log"
+	"log/slog"
 	"os"
 	"strings"
 )
@@ -19,7 +19,8 @@ func Confirm(s string) bool {
 
 		response, err := reader.ReadString('\n')
 		if err != nil {
-			log.Fatal(err)
+			slog.Error("reading the answer", "error", err)
+			os.Exit(1)
 		}
 
 		response = strings.ToLower(strings.TrimSpace(response))