Initial commit: webtrees full diagram chart module

Interactive SVG family tree visualization using ELK (Sugiyama) for
layout and D3 for rendering. Shows ancestors, descendants, and siblings
in a single diagram with orthogonal bus-line connectors.

Features:
- Bidirectional tree traversal (ancestors + descendants + siblings)
- Generation-aligned layout with post-processing Y-snap
- Person cards with photos, names, dates, and hover bio cards
- "More ancestors" indicator for persons with hidden parents
- Pan/zoom navigation
- Docker dev environment

resources/js/modules/index.js

@@ -0,0 +1,30 @@
+/**
+ * Full Diagram — entry point.
+ *
+ * Reads embedded data from the page and initializes the chart.
+ */
+import Chart from "./lib/chart.js";
+
+async function init() {
+    const data = window.fullDiagramData;
+    const baseUrl = window.fullDiagramBaseUrl;
+
+    if (!data || !data.persons) {
+        console.error("Full Diagram: No tree data found.");
+        return;
+    }
+
+    try {
+        const chart = new Chart("#full-diagram-container", data, baseUrl);
+        await chart.render();
+    } catch (err) {
+        console.error("Full Diagram: Render failed", err);
+    }
+}
+
+// Initialize when DOM is ready
+if (document.readyState === "loading") {
+    document.addEventListener("DOMContentLoaded", init);
+} else {
+    init();
+}