Rename Append to Merge, replace strings_Join with slice_Join, and auto-detect non-TTY output

- Rename Append to Merge on Cookies, Headers, and Params types and simplify Parse to use direct append
- Replace strings_Join(sep, ...values) with slice_Join(slice, sep) for consistency with slice-based template functions
- Auto-enable quiet mode when stdout is not a terminal
- Remove ErrCLINoArgs check to allow running sarin without arguments
- Add -it flag to Docker examples in docs

internal/sarin/sarin.go

@@ -3,6 +3,7 @@ package sarin
 import (
 	"context"
 	"net/url"
+	"os"
 	"strconv"
 	"strings"
 	"sync"
@@ -13,6 +14,7 @@ import (
 	"github.com/charmbracelet/bubbles/spinner"
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
+	"github.com/charmbracelet/x/term"
 	"github.com/valyala/fasthttp"
 	"go.aykhans.me/sarin/internal/script"
 	"go.aykhans.me/sarin/internal/types"
@@ -155,6 +157,10 @@ func (q sarin) Start(ctx context.Context) {
 	var messageChannel chan runtimeMessage
 	var sendMessage messageSender
 
+	if !q.quiet && !term.IsTerminal(os.Stdout.Fd()) {
+		q.quiet = true
+	}
+
 	if q.quiet {
 		sendMessage = func(level runtimeMessageLevel, text string) {}
 	} else {

internal/sarin/template.go

@@ -62,10 +62,6 @@ func NewDefaultTemplateFuncMap(randSource rand.Source, fileCache *FileCache) tem
 		},
 		"strings_TrimPrefix": strings.TrimPrefix,
 		"strings_TrimSuffix": strings.TrimSuffix,
-		"strings_Join": func(sep string, values ...string) string {
-			return strings.Join(values, sep)
-		},
-
 		// Dict
 		"dict_Str": func(values ...string) map[string]string {
 			dict := make(map[string]string)
@@ -83,6 +79,7 @@ func NewDefaultTemplateFuncMap(randSource rand.Source, fileCache *FileCache) tem
 		"slice_Str":  func(values ...string) []string { return values },
 		"slice_Int":  func(values ...int) []int { return values },
 		"slice_Uint": func(values ...uint) []uint { return values },
+		"slice_Join": strings.Join,
 
 		// File
 		// file_Base64 reads a file (local or remote URL) and returns its Base64 encoded content.