fix(flowchart): ensure rendered SVG + selection visibility; force light theme in canvas; v4.9.5

v4.9.4 shipped three interaction bugs in the Flow Chart panel that combined to make it look broken at runtime: (1) .flowchart-preview-render had no min-height, so the Mermaid SVG clipped to 0 when the sidebar flex column shrank; (2) the canvas + preview hosts inherited the body.theme-concreteinfo dark theme, producing dark-on-dark nodes; (3) .flowchart-node.selected only set a 2px stroke on the rect's existing dark fill, which was effectively invisible.

Fix: styles-sidebar.css adds min-height: 120px on .flowchart-preview-render; forces a light background on .flowchart-canvas-host / .flowchart-preview-host with !important so theme inheritance cannot override it; forces explicit white fills and dark strokes on .flowchart-node rect/polygon/text and .flowchart-edge so labels read against any background; selection now changes fill (#e3f0ff) AND bumps stroke-width to 3 on both nodes and edges. renderer.js renderFlowChartMermaid now always initializes Mermaid with theme: 'default' regardless of body class — keeps the Mermaid SVG light to match the CSS-forced canvas surface.

Three new CSS regression tests in tests/flowchart-panel.test.js read the shipped stylesheet and assert the three structural invariants (non-zero min-height on render target, !important light background on canvas+preview hosts, fill + stroke-width >= 3 on .flowchart-node.selected).

Tradeoff: the flowchart surface is now always light, diverging from body theme. Visibility of a working editor is the priority per user direction.

Amit Haridas

package.json

@@ -1,6 +1,6 @@
 {
   "name": "markdown-converter",
-  "version": "4.9.4",
+  "version": "4.9.5",
   "description": "Professional Markdown editor and universal file converter with PDF editing, batch processing, and syntax highlighting",
   "main": "src/main.js",
   "scripts": {