(#3) - templating

modules/Templating/RsvTemplateElement.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Reservair\Templating;
+
+/** A registered handler for a hyphenated custom element tag. */
+interface RsvTemplateElement {
+    /** Renders the element to a trusted HTML string given the resolved symbol table. */
+    public function render(RsvTemplateSymbols $symbols): string;
+
+    /**
+     * Returns the symbol names this element understands — used by validation to
+     * report missing or extra attributes.
+     *
+     * @return list<string>
+     */
+    public function symbols(): array;
+}