wip: P1 feature batch — retry, search, code symbols, diff/status/test commands, tool output head+tail

- retry logic for transient LLM errors (openai.go)
- file_search context_lines + max_results (file.go)
- FormatResult now preserves head+tail with omitted bytes (tools.go)
- /status /diff /test slash commands wired (workflow.go, app.go)
- CodeSymbolsTool for Go package/type/func listing (code.go)
- README updated with v0.0.4 features

internal/tui/app_test.go

@@ -2,6 +2,9 @@ package tui
 
 import (
 	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -271,6 +274,59 @@ func TestSlashCommandSuggestions(t *testing.T) {
 	}
 }
 
+func TestWorkflowStatusDiffAndTestCommands(t *testing.T) {
+	if _, err := exec.LookPath("git"); err != nil {
+		t.Skip("git not installed")
+	}
+	dir := t.TempDir()
+	runInDir(t, dir, "git", "init")
+	runInDir(t, dir, "git", "config", "user.email", "agentu@example.test")
+	runInDir(t, dir, "git", "config", "user.name", "agentu")
+	if err := os.WriteFile(filepath.Join(dir, "go.mod"), []byte("module example.com/p1\n\ngo 1.26\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "main_test.go"), []byte("package p1\n\nimport \"testing\"\n\nfunc TestOK(t *testing.T) {}\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	runInDir(t, dir, "git", "add", ".")
+	runInDir(t, dir, "git", "commit", "-m", "init")
+	if err := os.WriteFile(filepath.Join(dir, "main_test.go"), []byte("package p1\n\nimport \"testing\"\n\nfunc TestOK(t *testing.T) { t.Log(\"changed\") }\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	m := newModel(context.Background(), nil, Options{ModelName: "test-model", WorkingDir: dir})
+	status, err := m.handleStatusCommand(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(status, "main_test.go") {
+		t.Fatalf("status missing changed file:\n%s", status)
+	}
+	diff, err := m.handleDiffCommand(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(diff, "changed") {
+		t.Fatalf("diff missing changed content:\n%s", diff)
+	}
+	out, err := m.handleTestCommand(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(out, "$ go test ./...") {
+		t.Fatalf("test output missing default command:\n%s", out)
+	}
+}
+
+func runInDir(t *testing.T, dir string, name string, args ...string) {
+	t.Helper()
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	if output, err := cmd.CombinedOutput(); err != nil {
+		t.Fatalf("%s %v failed: %v\n%s", name, args, err, output)
+	}
+}
+
 func TestModelCommand(t *testing.T) {
 	m := newModel(context.Background(), nil, Options{ModelName: "test-model", Yolo: true})
 	m.input.SetValue("/model")