refactor: split monolithic main.go into modular structure

Refactored 800+ line main.go into clean, domain-separated files:
- main.go (96 lines) - Entry point and command router only
- types.go - Type definitions and data structures
- client.go - HTTP client and request handling
- cmd_kv.go - Key-value operations (get/put/delete)
- cmd_meta.go - Resource metadata commands
- cmd_user.go - User management commands
- cmd_profile.go - Profile management
- cmd_cluster.go - Cluster operations (members/health)
- cmd_system.go - System commands (connect/auth/help)
- utils.go - Shared utilities (parsing, colors, completion)

No functional changes, pure reorganization for maintainability.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

utils.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/chzyer/readline"
+	"github.com/fatih/color"
+)
+
+// Color helpers
+var (
+	cyan    = color.New(color.FgCyan).SprintFunc()
+	green   = color.New(color.FgGreen).SprintFunc()
+	yellow  = color.New(color.FgYellow).SprintFunc()
+	red     = color.New(color.FgRed).SprintFunc()
+	magenta = color.New(color.FgMagenta).SprintFunc()
+)
+
+// parseCommand parses command line respecting quotes
+func parseCommand(line string) []string {
+	var parts []string
+	var current strings.Builder
+	var quoteChar rune = 0 // Use a rune to store the active quote character (' or ")
+
+	for _, ch := range line {
+		switch {
+		// If we see a quote character
+		case ch == '\'' || ch == '"':
+			if quoteChar == 0 {
+				// Not currently inside a quoted string, so start one
+				quoteChar = ch
+			} else if quoteChar == ch {
+				// Inside a quoted string and found the matching quote, so end it
+				quoteChar = 0
+			} else {
+				// Inside a quoted string but found the *other* type of quote, treat it as a literal character
+				current.WriteRune(ch)
+			}
+		// If we see a space or tab and are NOT inside a quoted string
+		case (ch == ' ' || ch == '\t') && quoteChar == 0:
+			if current.Len() > 0 {
+				parts = append(parts, current.String())
+				current.Reset()
+			}
+		// Any other character
+		default:
+			current.WriteRune(ch)
+		}
+	}
+
+	// Add the last part if it exists
+	if current.Len() > 0 {
+		parts = append(parts, current.String())
+	}
+
+	return parts
+}
+
+// printJSONError displays a user-friendly JSON parsing error with helpful hints
+func printJSONError(input string, err error) {
+	fmt.Println(red("❌ Invalid JSON:"), err)
+	fmt.Println()
+
+	// Show what was received
+	if len(input) > 100 {
+		fmt.Println(yellow("Received:"), input[:100]+"...")
+	} else {
+		fmt.Println(yellow("Received:"), input)
+	}
+	fmt.Println()
+
+	// Provide helpful hints based on common errors
+	errMsg := err.Error()
+
+	if strings.Contains(errMsg, "looking for beginning of") ||
+		strings.Contains(errMsg, "invalid character") {
+		fmt.Println(cyan("💡 Tip:"), "JSON with spaces needs quotes:")
+		fmt.Println(green("  ✓ Correct:"), "put key '{\"hello\":\"world\"}'")
+		fmt.Println(green("  ✓ Correct:"), "put key '{\"a\":1,\"b\":2}'")
+		fmt.Println(green("  ✓ Compact:"), "put key {\"a\":1,\"b\":2}  (no spaces)")
+		fmt.Println(red("  ✗ Wrong:  "), "put key {\"a\": 1, \"b\": 2}  (spaces without quotes)")
+	} else if strings.Contains(errMsg, "unexpected end of JSON") {
+		fmt.Println(cyan("💡 Tip:"), "JSON appears incomplete or cut off")
+		fmt.Println(green("  Check:"), "Are all brackets/braces matched? {}, []")
+		fmt.Println(green("  Check:"), "Did spaces split your JSON into multiple arguments?")
+	} else {
+		fmt.Println(cyan("💡 Tip:"), "Wrap JSON in quotes for complex values:")
+		fmt.Println(green("  Single quotes:"), "put key '{\"your\":\"json\"}'")
+		fmt.Println(green("  Double quotes:"), "put key \"{\\\"your\\\":\\\"json\\\"}\"")
+	}
+}
+
+// Auto-completion setup
+var completer = readline.NewPrefixCompleter(
+	readline.PcItem("connect"),
+	readline.PcItem("auth"),
+	readline.PcItem("profile",
+		readline.PcItem("add"),
+		readline.PcItem("use"),
+		readline.PcItem("remove"),
+	),
+	readline.PcItem("get"),
+	readline.PcItem("put"),
+	readline.PcItem("delete"),
+	readline.PcItem("meta",
+		readline.PcItem("get"),
+		readline.PcItem("set",
+			readline.PcItem("--owner"),
+			readline.PcItem("--group"),
+			readline.PcItem("--permissions"),
+		),
+	),
+	readline.PcItem("members"),
+	readline.PcItem("health"),
+	readline.PcItem("user",
+		readline.PcItem("get"),
+		readline.PcItem("create"),
+	),
+	readline.PcItem("help"),
+	readline.PcItem("exit"),
+	readline.PcItem("quit"),
+	readline.PcItem("clear"),
+)