fix(psalm): bump enforced minimum PHP version to 8.3

CI step "Check enforcement of minimum PHP version 8.3 in psalm.xml"
greps for phpVersion="8.3" in psalm.xml and fails when absent.
NC35 (info.xml min-version) requires PHP 8.3+, so align psalm config.

Assisted-by: ClaudeCode:claude-opus-4-8
Signed-off-by: skjnldsv <skjnldsv@protonmail.com>

Author: skjnldsv

psalm.xml

@@ -9,7 +9,7 @@
 	findUnusedBaselineEntry="true"
 	findUnusedCode="false"
 	resolveFromConfigFile="true"
-	phpVersion="8.2"
+	phpVersion="8.3"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xmlns="https://getpsalm.org/schema/config"
 	xsi:schemaLocation="https://getpsalm.org/schema/config vendor-bin/psalm/vendor/vimeo/psalm/config.xsd"