Prepare for Matomo 6

[sgiehl]

Description

Prepares LoginLdap for Matomo 6.

This branch existed before 6.x-dev did, so it has been restacked: 6.x-dev was created in parity with 5.x-dev, and the eight existing preparation commits were rebased onto it. The branch now carries the 28 5.x-dev commits it previously missed — including the password hash logic change (#AS-649), synchronising LDAP users by the resolved Matomo login (#AS-633) and the password-confirmation default (#PG-5346).

On top of the restack:

• plugin.json — 6.0.0, requiring >=6.0.0-b1,<7.0.0-b1. The -b1 lower bound matters: a plain >=6.0.0 sorts above 6.0.0-b1 and would disable the plugin against a beta core.
• Test workflow — the PHP matrix, the UI/JS jobs and the upload-artifacts condition now use the matomo6_min_php / matomo6_max_php aliases instead of pinned literals, so they track core rather than drifting. The generator comment in the header was updated to match.
• phpstan.neon — phpVersion raised to 80100, and the excludePaths pruned. PHPStan 2 (bundled with Matomo 6) fails hard on an excludePaths entry that matches nothing, so on the previous config it refused to run at all. The absent vendor/ entry was dropped and github-action-tests/ marked optional with (?) — it does not exist in the repo but checkout_matomo.sh creates it during a CI run.
• CHANGELOG.md — a 6.0.0 entry, following the undated shape this repository used for the 5.0.0 major-preparation entry.
• PHPUnit 9 — assertRegExp() → assertMatchesRegularExpression().
• Ldap\Client::$connectionResource — docblock corrected to \LDAP\Connection|false|null. PHP 8.1 changed ldap_connect() from returning a resource to an LDAP\Connection object; the stale @var resource produced nine false PHPStan errors once phpVersion was raised.
• vue/dist — rebuilt from the restacked sources, so the minified bundle matches the merged vue/src.

Notes for review

• The Vue build reports no TypeScript errors, and the code-compatibility sweep against the Matomo 6 breaking-changes catalogue found nothing beyond the PHPUnit assertion rename. Controller extends Login\Controller, which has no #[JsonResponse] actions, so the new controller contract does not apply here.
• PHPStan reports 21 pre-existing errors, down from 24 before this branch. None are new. This repository has no PHPStan CI workflow, so these are not gated here — Add PHPStan CI check and pre-push hook, PG-4897 [no_release] #457 adds that check against 5.x-dev separately.
• Local verification: PHPCS clean (63 sniffs, 0 errors), vue:build clean, plugin:activate succeeds, core:update reports no pending migrations. The integration suite was not run locally — it needs a running slapd, which setup_ldap.sh provides in CI.
• Every commit is marked [ignore_release]: none of this changes plugin behaviour, and nothing can be released for Matomo 6 until core ships.
• PRs Login redesign #461 and Update the confirm password screenshots for the refreshed login layout #462 target prepare6x as their base and were rebased under; their diffs will have recomputed.

Checklist

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