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

README.md

@@ -90,6 +90,7 @@ go run ./cmd/agentu [flags]
 - `--theme light|dark` selects the TUI theme. Default: `light`.
 - `--plain` uses the simple line-based REPL instead of the TUI.
 - `--yolo` enables automatic file writes and shell execution.
+- `--resume <id>` resumes a saved session from `~/.agentu/sessions`.
 
 ## TUI Controls
 
@@ -103,10 +104,17 @@ go run ./cmd/agentu [flags]
 Slash commands:
 
 - `/clear` resets conversation history.
+- `/status` shows changed files with `git status --short`.
+- `/diff [--stat] [path...]` shows the unstaged git diff.
+- `/test [command...]` runs a project test command; defaults to `go test ./...` for Go modules or `npm test` for Node projects.
 - `/model` shows current provider, model, thinking, and switch usage.
 - `/model provider <name>` switches provider for the current session.
 - `/model model <name>` or `/model <name>` switches model for the current session.
 - `/model thinking <none|middle|high|xhigh|max>` changes thinking for the current session.
+- `/sessions` lists saved sessions.
+- `/resume [id]` resumes by ID or opens an interactive picker.
+- `/rename <name>` renames the current session.
+- `/new` saves the current session and starts a fresh one.
 - `/exit` or `/quit` exits.
 
 ## Local Tools
@@ -115,7 +123,8 @@ Read-only tools are available by default:
 
 - `file_read`
 - `file_list`
-- `file_search`
+- `file_search` with optional `context_lines` and `max_results`
+- `code_symbols` for Go packages, imports, types, functions, and methods
 
 Web tools are also available in read-only mode: