v0.0.1: agentu mvp

Add OpenAI-compatible providers, TUI, slash commands, and model switching.
Add local file tools plus optional yolo shell execution.
Document config, usage, and development workflow.

internal/tools/paths.go

@@ -0,0 +1,15 @@
+package tools
+
+import (
+	"path/filepath"
+)
+
+func resolvePath(baseDir, path string) (string, error) {
+	if path == "" {
+		path = "."
+	}
+	if filepath.IsAbs(path) {
+		return filepath.Clean(path), nil
+	}
+	return filepath.Abs(filepath.Join(baseDir, path))
+}