Fix the 5.0.11 update on Matomo versions before 5.9 and raise PHPStan to level 5

[snake14]

Description

Fixes the plugin's 5.0.11 update failing on Matomo versions before 5.9. It called settings methods that only exist from Matomo 5.9, so updating the plugin on an older Matomo 5 stopped with an error. The update now uses methods every supported Matomo 5 version has.

The fix edits the existing 5.0.11 update rather than adding a new one: on the affected versions the update fails before completing, and Matomo does not record it as done, so a later update would never be reached, and installs that already ran it are unaffected because it does the same thing. It now also writes through the same settings storage the 5.1.0 and 5.2.0 updates save from, so an install catching up on several updates at once keeps the value, and it does so without starting a cloud IP range sync during the update.

The rest of the change brings the 5.x branch into line with the shared plugin CI setup. The plugin now ships the shared pre-push hook and its created/modified PHPStan configs, and CI checks the hook against the canonical copy (verify-hook). The base PHPStan level rises from 0 to 5; the remaining findings are cleared without changing behaviour: two empty() checks that could never be false at that point, and four 'strlen' filters replaced with !== '' closures (the values are already trimmed strings).

Issue No

PG-4897

Steps to Replicate the Issue

1. On Matomo 5.8 or earlier, with no block_headless value stored or configured, update TrackingSpamPrevention from a version before 5.0.11. The new tests in UpdatesTest cover the update, including 5.0.11 followed by 5.1.0 in one run.
2. Expected: the update completes and block_headless is stored as disabled.
3. Actual before this change: the update fails with "Call to undefined method PluginSettingsTable::loadValue()".

Checklist

• [✔] Tested locally or on demo2/demo3?
• [✔] New test case added/updated?
• [NA] Are all newly added texts included via translation?
• [NA] Are text sanitized properly? (Eg use of v-text v/s v-html for vue)
• [✔] Version bumped?
• [✔] I have understood, reviewed, and tested all AI outputs before use
• [✔] All AI instructions respect security, IP, and privacy rules
• [NA] Documentation updated?