feat(mcp): auto-generate interactive widget from JSON data (#2076)

* feat(mcp): auto-visualize JSON data via widget agent

When McpDataPanel receives JSON results and widget key is configured,
automatically pipe the data through the widget agent to generate an
interactive HTML visualization instead of showing raw JSON.

- Uses pro tier (Chart.js iframe) if wm-pro-key is set, basic (SVG/CSS)
  otherwise
- Caches generated HTML by content hash to avoid regenerating on refresh
  cycles when data hasn't changed
- Falls back to raw JSON display on error or if widget not configured
- Shows radar loading animation during generation

* fix(mcp): always use pro tier for auto-visualization

MCP panel is a PRO-only feature, so auto-visualization always uses
pro tier (Chart.js iframe, full interactivity) with X-Pro-Key header.
Removes basic tier fallback path that was incorrect.

src/styles/main.css

@@ -20372,6 +20372,50 @@ body.has-breaking-alert .panels-grid {
   margin: 0;
 }
 
+.mcp-panel-visualizing {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 10px;
+  min-height: 120px;
+  opacity: 0.7;
+}
+
+.mcp-vis-label {
+  font-size: 12px;
+  color: var(--text-muted);
+}
+
+.mcp-panel-widget {
+  padding: 0 !important;
+  overflow: hidden;
+  display: flex;
+  flex-direction: column;
+}
+
+.mcp-panel-widget .wm-widget-shell {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  min-height: 240px;
+}
+
+.mcp-panel-widget .wm-widget-body,
+.mcp-panel-widget .wm-widget-generated {
+  flex: 1;
+  overflow-y: auto;
+  padding: 8px 10px;
+}
+
+.mcp-panel-widget iframe {
+  width: 100%;
+  min-height: 260px;
+  border: none;
+  display: block;
+  flex: 1;
+}
+
 /* ── MCP Presets ───────────────────────────────────── */
 .mcp-presets-section {
   display: flex;