fix: ESC doesn't kill panel mid-run, remove stale #inbox test

runner.js: the Escape handler now checks panel.style.display !== 'none'
before closing. During the test run the panel is hidden (display:none)
but the variable is truthy — synthetic Escape events dispatched by
tests (e.g. "closes on ESC") were triggering close() mid-run, removing
the panel entirely so results never showed.

quick-capture.test.js: the "Enter creates card with #inbox tag" test
was asserting found.tags contains 'inbox', but the #inbox auto-tag
was removed in 0.9.17. Renamed to "Enter creates card in active
bucket" and dropped the stale tags assertion.

chore: bump version to 0.9.20

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/plugins/tests/runner.js

@@ -496,7 +496,7 @@ document.addEventListener('keydown', e => {
         e.preventDefault();
         panel ? close() : open();
     }
-    if (e.key === 'Escape' && panel) {
+    if (e.key === 'Escape' && panel && panel.style.display !== 'none') {
         e.preventDefault();
         e.stopPropagation();
         close();