fix: PHP 8.4 PHPUnit green after strict_types corpus curation

[ecartz]

Description

The Rector/PHP-CS-Fixer corpus curation on remote-test-2026-08-31 added declare(strict_types=1) broadly, which broke runtime type coercion in several framework entry points and test fixtures. This PR restores PHP 8.4 compatibility so vendor/bin/phpunit exits 0.

Changes:

• Remove strict_types from files that intentionally coerce dynamic values (BaseConfig, Parser, Filters, CodeIgniter, ControllerTestTrait, test autorouting controller)
• Cast env/CLI values where PHP 8.4 now enforces scalar types (BaseConfig::initEnvValue, CLI error backtrace numbering)
• Restore unsorted imports in tests/_support/Commands/Foobar.php so sort-imports publish tests behave as intended
• Allow class unserialization in FileHandler for FactoriesCache config caching
• Update deprecation logging test to avoid str_contains(null) TypeError under strict test files
• Flush Redis in PredisHandlerTest::setUp() to isolate key-count assertions

Verification

composer install --no-interaction
vendor/bin/phpunit

• Exit code: 0
• Tests: 7770
• Assertions: 18969
• Skipped: 121
• Runtime: ~63s
• Coverage log: build/logs/clover.xml
• Coverage text: build/coverage/coverage.txt

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide