https://orkes.atlassian.net/browse/CCOR-13360

[ajlai-orkes]

Workflow diagram 'Export to image' has multiple issues (unresponsive, draft export fails, switch node unreadable)

Pull Request type

• Bugfix
• Feature
• Refactoring (no functional changes, no api changes)
• Build related changes
• WHOSUSING.md
• Other (please describe):

NOTE: Please remember to run ./gradlew spotlessApply to fix any format violations.

Changes in this PR

• Fixes workflow Export to image so SWITCH diamonds stay white with a readable border instead of rendering as a solid black shape. StarShape now paints an explicit fill and uses a CSS drop-shadow, because dom-to-image inlines computed styles onto its clone and a -inherited fill was being pinned to the initial value (black).
• Makes exports that previously failed silently actually succeed. dom-to-image was writing SVG into a data: URI without fully encoding the payload, so a sequence like %3C was percent-decoded a second time into <, the SVG failed to load, and the library rejected with an empty image error event. The payload is now encodeURIComponent’d, matching html-to-image.
• Shows an error toast when export still fails, with a useful reason instead of [object Event] / “check the console”.
• Adds a Playwright check that clicks Export to image, waits for the download, and snapshots the PNG. The comparison is tight (maxDiffPixels: 200) so a black diamond (~1.4% of a 2400×1161 image) cannot hide under the suite’s 2% screenshot tolerance.