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/utils/strings.go

@@ -0,0 +1,62 @@
+package utils
+
+import "strings"
+
+func Truncate(s string, maxLen int) string {
+	if len(s) <= maxLen {
+		return s
+	}
+	if maxLen < 0 {
+		return ""
+	}
+	return s[:maxLen] + "..."
+}
+
+// SafeTruncate safely truncates string to maxLen, avoiding panic and UTF-8 corruption.
+func SafeTruncate(s string, maxLen int) string {
+	if maxLen <= 0 || s == "" {
+		return ""
+	}
+
+	runes := []rune(s)
+	if len(runes) <= maxLen {
+		return s
+	}
+
+	if maxLen < 4 {
+		return string(runes[:1])
+	}
+
+	cutoff := maxLen - 3
+	if cutoff <= 0 {
+		return string(runes[:1])
+	}
+	if len(runes) <= cutoff {
+		return s
+	}
+	return string(runes[:cutoff]) + "..."
+}
+
+// SanitizeOutput removes ANSI escape sequences and control characters.
+func SanitizeOutput(s string) string {
+	var result strings.Builder
+	inEscape := false
+	for i := 0; i < len(s); i++ {
+		if s[i] == '\x1b' && i+1 < len(s) && s[i+1] == '[' {
+			inEscape = true
+			i++ // skip '['
+			continue
+		}
+		if inEscape {
+			if (s[i] >= 'A' && s[i] <= 'Z') || (s[i] >= 'a' && s[i] <= 'z') {
+				inEscape = false
+			}
+			continue
+		}
+		// Keep printable chars and common whitespace.
+		if s[i] >= 32 || s[i] == '\n' || s[i] == '\t' {
+			result.WriteByte(s[i])
+		}
+	}
+	return result.String()
+}