[jakubboucek]

This PR responds to Copilot's review of #102: printing the extension list does not fail when a required extension is missing, and individual functional tests can skip unavailable extensions. A mandatory inventory test now fails for both missing and unexpected extensions, including memcached, xdebug, and spx where required.

This PR targets update-php, the branch of #102.

Changes

• Define expected extensions in a readable NEON configuration: common extensions, cumulative version/variant rules, and explicit exceptions applied last. New PHP versions are evaluated automatically without adding a profile to an allowlist.
• Support nested all/any conditions, list shorthand for all, version comparisons, and positive/negative variant flags. Reject malformed configuration and conflicting rules; document exceptions and advanced examples.
• Pass the image reference through IMAGE_NAME and validate it against the runtime PHP version. test-php.sh [tag] tests one image; without arguments it tests all 15 configured variants and reports any failure.
• Run the same suite in all ten maintained build scripts before publishing, preserving the NO_TEST switch.
• Pin nette/neon to stable 3.4.8. Its PHP 8.6 behavior was verified despite its declared PHP version constraint ending at 8.5; test dependencies are prepared on the host using the PHP 8.1 Composer platform configuration.

Validation

• Full suite: 26 tests in each of the 15 PHP 8.2–8.6 base, CLI, and debug images, with existing expected skips.
• Negative checks: missing/unexpected debug extensions and missing image identity fail the inventory test.
• Build test phases exercised for all ten scripts with rebuilding and publishing disabled; mocked Docker checks verified that failed tests prevent publishing and NO_TEST bypasses the suite.
• NEON documentation examples parsed and evaluated against representative version/variant combinations.