Add integration: use a header-action href instead of the window.location.assign handler #1324

Plan: https://github.com/ConductionNL/readonly-mirror-wilco-claude-plans/tree/dev-mirror/issues/github/stackiq/stackiq-1324/
Jira: https://conduction.atlassian.net/browse/WOO-591 (Rotterdam: live TOPdesk connection in stackiq; origin WOO-589)

Problem

The Integrations page's Add integration header action leaves stackiq for integriq's Connections overview (/apps/integriq/connections?app=stackiq&link=1) through a JavaScript handler: the manifest entry add-integration in src/manifest.d/connection-registry.json names the function handler openIntegriqConnections, built by createConnectionHandlers() in src/services/connectionRegistry.js and wired in src/customComponents.js with window.location.assign. It is announced as a button, and users cannot middle-click it, open it in a new tab, copy its address or bookmark it.

@conduction/nextcloud-vue now supports this directly: ConductionNL/nextcloud-vue#1314 was finished by ConductionNL/nextcloud-vue#1794 (in development since 2026-10-20). A headerActions[] entry with href renders as a real <a href>, an instance path is resolved through generateUrl(), and the link runs no handler. The comment in src/customComponents.js already announces this switch.

Proposal

• Bump @conduction/nextcloud-vue to the first release that contains feat: let a manifest header action render as a link (href) nextcloud-vue#1794 (stackiq is locked at 2.73.1; the change is not published yet).
• Replace "handler": "openIntegriqConnections" on add-integration with "href": "/apps/integriq/connections?app=stackiq&link=1" (opens in place; no target).
• Remove createConnectionHandlers() / openIntegriqConnections and their wiring in src/customComponents.js if nothing else uses them, and update tests/vitest/connectionRegistry.spec.js and the adopt-connection-registry spec references accordingly.
• Check that src/manifest.d/connection-registry.json still validates against the manifest schema of the bumped library (2.135.0 adds href on header actions).

Done when

• Add integration on the Integrations page is an <a href> that points to integriq's Connections overview with the instance root applied (also under a subdirectory install), opens in place, and can be middle-clicked, opened in a new tab and copied.
• No window.location.assign remains for this action.