tests: rebind runner to Ctrl+Shift+Alt+T and cover recent fixes

Plugin loader + runner shortcut moves to Ctrl+Shift+Alt+T (the old
Ctrl+Shift+T conflicts with the browser "reopen closed tab"). Loader
now imports runner.js *without* the cache-busting query so it picks
up the same module instance the test files register their suites
into — previously the shortcut opened a fresh runner with an empty
suites array and reported 0/0 passed.

New / fixed coverage:
- card-interactions: favorite toggle assertion is now case-insensitive
  (context menu was capitalized to "Unfavorite"/"Favorite" earlier);
  done-badge test guards against state.hideDone / hideTagged that would
  filter the test card off the board; new test for the always-on
  Mark done / Unmark done toggle on a card without due_date.
- context-menu: copy-text action exists; copy-text strips fenced code
  blocks, image markdown and inline #tags. Mocks navigator.clipboard
  via Object.defineProperty so the assertion works without a focused
  / secure-context clipboard.
- export: round-trip preserves a custom bucket color (covers the import
  handler regression that was wiping bucket colors on every test run).
- theme: design preset selection persists in localStorage across
  settings open/close, refreshPresetSelect ignores unknown keys.
  afterEach restores both hyprcrd-design-active-preset and
  hyprcrd-design so a test run can't permanently swap the user's
  design.

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

public/plugins/tests/plugin.json

@@ -1,7 +1,7 @@
 {
     "name": "tests",
     "version": "1.0.0",
-    "description": "UI + state test runner. Loads only when ?test query param is present or Ctrl+Shift+T is pressed.",
+    "description": "UI + state test runner. Loads only when ?test query param is present or Ctrl+Shift+Alt+T is pressed.",
     "frontend": {
         "js":   ["loader.js"],
         "css":  [],