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/guards.go

@@ -0,0 +1,91 @@
+package navigation
+
+import "strings"
+
+// Common route guards
+
+// AuthGuard checks if user is authenticated
+func AuthGuard(isAuthenticated func() bool) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		return isAuthenticated()
+	}
+}
+
+// RoleGuard checks if user has required role
+func RoleGuard(userRole func() string, requiredRole string) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		return userRole() == requiredRole
+	}
+}
+
+// PermissionGuard checks if user has specific permission
+func PermissionGuard(hasPermission func(permission string) bool, permission string) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		return hasPermission(permission)
+	}
+}
+
+// ParamValidationGuard validates route parameters
+func ParamValidationGuard(validator func(params map[string]string) bool) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		return validator(params)
+	}
+}
+
+// PathPrefixGuard checks if the current path starts with a specific prefix
+func PathPrefixGuard(prefix string) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		currentPath := GetCurrentPath()
+		return strings.HasPrefix(currentPath, prefix)
+	}
+}
+
+// CombineGuards combines multiple guards with AND logic
+func CombineGuards(guards ...RouteGuard) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		for _, guard := range guards {
+			if !guard(route, params) {
+				return false
+			}
+		}
+		return true
+	}
+}
+
+// AnyGuard combines multiple guards with OR logic
+func AnyGuard(guards ...RouteGuard) RouteGuard {
+	return func(route *Route, params map[string]string) bool {
+		for _, guard := range guards {
+			if guard(route, params) {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// Example usage patterns:
+
+// AdminOnlyGuard - combines authentication and role checks
+func AdminOnlyGuard(isAuth func() bool, userRole func() string) RouteGuard {
+	return CombineGuards(
+		AuthGuard(isAuth),
+		RoleGuard(userRole, "admin"),
+	)
+}
+
+// NumericIdGuard - validates that :id parameter is numeric
+func NumericIdGuard() RouteGuard {
+	return ParamValidationGuard(func(params map[string]string) bool {
+		if id, exists := params["id"]; exists {
+			// Simple numeric check
+			for _, char := range id {
+				if char < '0' || char > '9' {
+					return false
+				}
+			}
+			return len(id) > 0
+		}
+		return true // No id param, so validation passes
+	})
+}