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.go

@@ -28,6 +28,7 @@ type Options struct {
 	Yolo         bool
 	ThemeMode    ThemeMode
 	ModelManager ModelManager
+	WorkingDir   string
 }
 
 type ModelManager interface {
@@ -69,13 +70,14 @@ type message struct {
 }
 
 type model struct {
-	ctx       context.Context
-	agent     *agent.Agent
-	modelName string
-	yolo      bool
-	models    ModelManager
-	theme     theme
-	styles    styles
+	ctx        context.Context
+	agent      *agent.Agent
+	modelName  string
+	yolo       bool
+	models     ModelManager
+	workingDir string
+	theme      theme
+	styles     styles
 
 	viewport viewport.Model
 	input    textarea.Model
@@ -126,6 +128,9 @@ var slashCommands = []slashCommand{
 	{Name: "/resume", Description: "resume session"},
 	{Name: "/rename", Description: "rename session"},
 	{Name: "/new", Description: "new session"},
+	{Name: "/status", Description: "show changed files"},
+	{Name: "/diff", Description: "show unstaged diff"},
+	{Name: "/test", Description: "run project tests"},
 }
 
 func newModel(ctx context.Context, assistant *agent.Agent, opts Options) model {
@@ -155,17 +160,18 @@ func newModel(ctx context.Context, assistant *agent.Agent, opts Options) model {
 	vp.SetContent("")
 
 	return model{
-		ctx:       ctx,
-		agent:     assistant,
-		modelName: opts.ModelName,
-		yolo:      opts.Yolo,
-		models:    opts.ModelManager,
-		theme:     th,
-		styles:    st,
-		viewport:  vp,
-		input:     input,
-		spinner:   spin,
-		status:    "ready",
+		ctx:        ctx,
+		agent:      assistant,
+		modelName:  opts.ModelName,
+		yolo:       opts.Yolo,
+		models:     opts.ModelManager,
+		workingDir: opts.WorkingDir,
+		theme:      th,
+		styles:     st,
+		viewport:   vp,
+		input:      input,
+		spinner:    spin,
+		status:     "ready",
 	}
 }
 
@@ -763,6 +769,12 @@ func (m model) handleLocalCommand(input string) (string, error) {
 		return m.handleRenameCommand(fields[1:])
 	case "/new":
 		return m.handleNewCommand()
+	case "/status":
+		return m.handleStatusCommand(fields[1:])
+	case "/diff":
+		return m.handleDiffCommand(fields[1:])
+	case "/test":
+		return m.handleTestCommand(fields[1:])
 	default:
 		return "", fmt.Errorf("unknown command: %s", fields[0])
 	}