Initial iris repository structure

WASM reactive UI framework for Go:
- reactive/ - Signal[T], Effect, Runtime
- ui/ - Button, Text, Input, View, Canvas, SVG components
- navigation/ - Router, guards, history management
- auth/ - OIDC client for WASM applications
- host/ - Static file server

Extracted from arcadia as open-source component.

Co-Authored-By: Claude <noreply@anthropic.com>

navigation/history.go

@@ -0,0 +1,63 @@
+//build +js,wasm
+
+package navigation
+
+import (
+	"syscall/js"
+)
+
+type HistoryManager struct {
+	router *Router
+	window js.Value
+}
+
+func NewHistoryManager(router *Router) *HistoryManager {
+	return &HistoryManager{
+		router: router,
+		window: js.Global().Get("window"),
+	}
+}
+
+func (h *HistoryManager) Start() {
+	// Handle initial navigation
+	currentPath := h.getCurrentPath()
+	h.router.Navigate(currentPath)
+	
+	// Listen for browser back/forward events
+	h.window.Call("addEventListener", "popstate", js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		path := h.getCurrentPath()
+		h.router.Navigate(path)
+		return nil
+	}))
+}
+
+func (h *HistoryManager) PushState(path string) {
+	h.window.Get("history").Call("pushState", nil, "", path)
+	h.router.Navigate(path)
+}
+
+func (h *HistoryManager) ReplaceState(path string) {
+	h.window.Get("history").Call("replaceState", nil, "", path)
+	h.router.Navigate(path)
+}
+
+func (h *HistoryManager) Back() {
+	h.window.Get("history").Call("back")
+}
+
+func (h *HistoryManager) Forward() {
+	h.window.Get("history").Call("forward")
+}
+
+func (h *HistoryManager) getCurrentPath() string {
+	location := h.window.Get("location")
+	pathname := location.Get("pathname").String()
+	search := location.Get("search").String()
+	
+	path := pathname
+	if search != "" {
+		path += search
+	}
+	
+	return path
+}