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/executor/testhooks.go

@@ -0,0 +1,57 @@
+package executor
+
+import (
+	"context"
+	"os/exec"
+
+	backend "codeagent-wrapper/internal/backend"
+)
+
+type CommandRunner = commandRunner
+type ProcessHandle = processHandle
+
+func SetForceKillDelay(seconds int32) (restore func()) {
+	prev := forceKillDelay.Load()
+	forceKillDelay.Store(seconds)
+	return func() { forceKillDelay.Store(prev) }
+}
+
+func SetSelectBackendFn(fn func(string) (Backend, error)) (restore func()) {
+	prev := selectBackendFn
+	if fn != nil {
+		selectBackendFn = fn
+	} else {
+		selectBackendFn = backend.Select
+	}
+	return func() { selectBackendFn = prev }
+}
+
+func SetCommandContextFn(fn func(context.Context, string, ...string) *exec.Cmd) (restore func()) {
+	prev := commandContext
+	if fn != nil {
+		commandContext = fn
+	} else {
+		commandContext = exec.CommandContext
+	}
+	return func() { commandContext = prev }
+}
+
+func SetNewCommandRunner(fn func(context.Context, string, ...string) CommandRunner) (restore func()) {
+	prev := newCommandRunner
+	if fn != nil {
+		newCommandRunner = fn
+	} else {
+		newCommandRunner = func(ctx context.Context, name string, args ...string) commandRunner {
+			return &realCmd{cmd: commandContext(ctx, name, args...)}
+		}
+	}
+	return func() { newCommandRunner = prev }
+}
+
+func WithTaskLogger(ctx context.Context, logger *Logger) context.Context {
+	return withTaskLogger(ctx, logger)
+}
+
+func TaskLoggerFromContext(ctx context.Context) *Logger {
+	return taskLoggerFromContext(ctx)
+}