refactor: restructure codebase to internal/ directory with modular architecture

- Move all source files to internal/{app,backend,config,executor,logger,parser,utils}
- Integrate third-party libraries: zerolog, goccy/go-json, gopsutil, cobra/viper
- Add comprehensive unit tests for utils package (94.3% coverage)
- Add performance benchmarks for string operations
- Fix error display: cleanup warnings no longer pollute Recent Errors
- Add GitHub Actions CI workflow
- Add Makefile for build automation
- Add README documentation

Generated with SWE-Agent.ai

Co-Authored-By: SWE-Agent.ai <noreply@swe-agent.ai>

codeagent-wrapper/internal/config/config.go

@@ -0,0 +1,102 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// Config holds CLI configuration.
+type Config struct {
+	Mode               string // "new" or "resume"
+	Task               string
+	SessionID          string
+	WorkDir            string
+	Model              string
+	ReasoningEffort    string
+	ExplicitStdin      bool
+	Timeout            int
+	Backend            string
+	Agent              string
+	PromptFile         string
+	PromptFileExplicit bool
+	SkipPermissions    bool
+	Yolo               bool
+	MaxParallelWorkers int
+}
+
+// EnvFlagEnabled returns true when the environment variable exists and is not
+// explicitly set to a falsey value ("0/false/no/off").
+func EnvFlagEnabled(key string) bool {
+	val, ok := os.LookupEnv(key)
+	if !ok {
+		return false
+	}
+	val = strings.TrimSpace(strings.ToLower(val))
+	switch val {
+	case "", "0", "false", "no", "off":
+		return false
+	default:
+		return true
+	}
+}
+
+func ParseBoolFlag(val string, defaultValue bool) bool {
+	val = strings.TrimSpace(strings.ToLower(val))
+	switch val {
+	case "1", "true", "yes", "on":
+		return true
+	case "0", "false", "no", "off":
+		return false
+	default:
+		return defaultValue
+	}
+}
+
+// EnvFlagDefaultTrue returns true unless the env var is explicitly set to
+// false/0/no/off.
+func EnvFlagDefaultTrue(key string) bool {
+	val, ok := os.LookupEnv(key)
+	if !ok {
+		return true
+	}
+	return ParseBoolFlag(val, true)
+}
+
+func ValidateAgentName(name string) error {
+	if strings.TrimSpace(name) == "" {
+		return fmt.Errorf("agent name is empty")
+	}
+	for _, r := range name {
+		switch {
+		case r >= 'a' && r <= 'z':
+		case r >= 'A' && r <= 'Z':
+		case r >= '0' && r <= '9':
+		case r == '-', r == '_':
+		default:
+			return fmt.Errorf("agent name %q contains invalid character %q", name, r)
+		}
+	}
+	return nil
+}
+
+const maxParallelWorkersLimit = 100
+
+// ResolveMaxParallelWorkers reads CODEAGENT_MAX_PARALLEL_WORKERS. It returns 0
+// for "unlimited".
+func ResolveMaxParallelWorkers() int {
+	raw := strings.TrimSpace(os.Getenv("CODEAGENT_MAX_PARALLEL_WORKERS"))
+	if raw == "" {
+		return 0
+	}
+
+	value, err := strconv.Atoi(raw)
+	if err != nil || value < 0 {
+		return 0
+	}
+	if value > maxParallelWorkersLimit {
+		return maxParallelWorkersLimit
+	}
+	return value
+}