fix(workflow): support the Vue 3 workflow engine of Nextcloud 36

[YvesCesar]

Related: #130, #175

Nextcloud server master (future 36) migrated workflowengine to Vue 3 with CSS modules and a Pinia store (nextcloud/server, 2026-09-30). This broke three things here:

• The default trigger of new profile field flows was applied through #workflowengine.__vue__.$store (Vuex) and a click listener on .actions__item.colored. Neither exists anymore, so new flows silently kept the first entity/event (file) instead of "Profile field value updated".
• The card theme located cards through .actions__item, .icon and colored. On NC 36 the engine applies invert(100%) to operation icons on light backgrounds, which turns the dark core icons used by this app white on the light green card.
• The Playwright workflow tests relied on .actions__item.colored, .section.rule and .comparator, which are now hashed CSS module classes. This is why Playwright fails on main, independent of chore: add Nextcloud 36 support #175.

Changes

• New src/utils/workflowEngineStore.ts adapts both stores: Vuex (__vue__.$store, NC 32-35) and Pinia (__vue_app__ → $pinia, NC 36). The default trigger is now applied to the rule that was just created (addRule mutation / createNewRule action) instead of on a DOM click, and only when that rule belongs to a profile field operation, so drafts keep the trigger chosen by the admin when another flow is added.
• The card theme finds the cards through the operation heading and marks card, description and icon with its own classes, so it works with both engines.
• Unit tests for both adapters and for the default trigger logic.
• Playwright: new check that the flow card icon is masked with the text color, and the workflow spec uses selectors that work with both engines (heading + "Add new flow" button, combobox names of old and new engine, rule root class of old and new engine).

The custom element protocol (update:model-value, valid, invalid, detail: [value]) and the OCA.WorkflowEngine.registerCheck/registerOperator API are unchanged, so the check and operation editors need no change.

[vitormattos]

Solve first the follow comment:

#175 (review)

and merge the PR 175