Add memory graph visualization UI

src/dashboard/templates/memory.html

@@ -31,7 +31,19 @@
     {% endfor %}
   </div>
 
-  <!-- Search -->
+  <div class="mc-tabs" style="margin-bottom: 1rem;">
+      <button class="mc-tab-btn active" onclick="switchTab('list')">List View</button>
+      <button class="mc-tab-btn" onclick="switchTab('graph')">Graph View</button>
+    </div>
+
+    <!-- Graph View -->
+    <div id="graph-view" class="mc-panel" style="display:none; height: 500px; position: relative; overflow: hidden;">
+      <div id="memory-graph" style="width:100%; height:100%;"></div>
+      <div id="graph-tooltip" style="position: absolute; display: none; background: var(--bg-color); border: 1px solid var(--border-color); padding: 0.5rem; border-radius: 4px; pointer-events: none; z-index: 100; font-size: 0.8rem; max-width: 200px;"></div>
+    </div>
+
+    <div id="list-view">
+    <!-- Search -->
   <div class="mc-search-section">
     <form method="get" action="/memory" class="mc-search-form">
       <input 
@@ -120,8 +132,109 @@
     </div>
   </div>
 </div>
+</div>
 
+<script src="https://d3js.org/d3.v7.min.js"></script>
 <script>
+function switchTab(tab) {
+  document.querySelectorAll('.mc-tab-btn').forEach(b => b.classList.remove('active'));
+  event.target.classList.add('active');
+  if (tab === 'graph') {
+    document.getElementById('list-view').style.display = 'none';
+    document.getElementById('graph-view').style.display = 'block';
+    renderGraph();
+  } else {
+    document.getElementById('list-view').style.display = 'block';
+    document.getElementById('graph-view').style.display = 'none';
+  }
+}
+
+let graphRendered = false;
+async function renderGraph() {
+  if (graphRendered) return;
+  graphRendered = true;
+
+  const res = await fetch('/memory/graph_data');
+  const data = await res.json();
+
+  const width = document.getElementById('memory-graph').clientWidth;
+  const height = document.getElementById('memory-graph').clientHeight;
+
+  const svg = d3.select("#memory-graph")
+    .append("svg")
+    .attr("width", width)
+    .attr("height", height);
+
+  const simulation = d3.forceSimulation(data.nodes)
+    .force("link", d3.forceLink(data.links).id(d(d.id)).distance(50))
+    .force("charge", d3.forceManyBody().strength(-100))
+    .force("center", d3.forceCenter(width / 2, height / 2));
+
+  const link = svg.append("g")
+    .attr("stroke", "var(--border-color)")
+    .attr("stroke-opacity", 0.6)
+    .selectAll("line")
+    .data(data.links)
+    .join("line")
+    .attr("stroke-width", d => Math.sqrt(d.value));
+
+  const node = svg.append("g")
+    .attr("stroke", "#fff")
+    .attr("stroke-width", 1.5)
+    .selectAll("circle")
+    .data(data.nodes)
+    .join("circle")
+    .attr("r", 8)
+    .attr("fill", d => {
+      if (d.type === 'fact') return '#ff4444';
+      if (d.type === 'conversation') return '#44ff44';
+      return '#4444ff';
+    })
+    .call(d3.drag()
+      .on("start", dragstarted)
+      .on("drag", dragged)
+      .on("end", dragended));
+
+  const tooltip = d3.select("#graph-tooltip");
+
+  node.on("mouseover", (event, d) => {
+    tooltip.style("display", "block")
+      .html("<strong>" + d.type.toUpperCase() + "</strong><br>" + d.content)
+      .style("left", (event.pageX - 250) + "px")
+      .style("top", (event.pageY - 100) + "px");
+  }).on("mouseout", () => {
+    tooltip.style("display", "none");
+  });
+
+  simulation.on("tick", () => {
+    link
+      .attr("x1", d => d.source.x)
+      .attr("y1", d => d.source.y)
+      .attr("x2", d => d.target.x)
+      .attr("y2", d => d.target.y);
+
+    node
+      .attr("cx", d => d.x)
+      .attr("cy", d => d.y);
+  });
+
+  function dragstarted(event) {
+    if (!event.active) simulation.alphaTarget(0.3).restart();
+    event.subject.fx = event.subject.x;
+    event.subject.fy = event.subject.y;
+  }
+  function dragged(event) {
+    event.subject.fx = event.x;
+    event.subject.fy = event.y;
+  }
+  function dragended(event) {
+    if (!event.active) simulation.alphaTarget(0);
+    event.subject.fx = null;
+    event.subject.fy = null;
+  }
+}
+
+function deleteFact(id) {
 function deleteFact(id) {
   if (!confirm('Delete this fact?')) return;
   fetch('/memory/fact/' + id, { method: 'DELETE' })