Add 5 Doctrine + Symfony-config rules

[TomasVotruba]

Adds 5 rules extracted from a real Symfony/Doctrine app.

Doctrine

• NoStringTargetEntityRule — a #[ManyToOne/OneToMany/OneToOne/ManyToMany] association must use Target::class, not a string targetEntity.
• NoReadonlyEntityClassRule — a Doctrine entity (recognized by #[ORM\Entity] or a public static loadMetadata()) must not be a readonly class, since Doctrine hydrates via reflection without the constructor.

Symfony / config closures

• PreferClassInDefinitionFetchRule — $container->getDefinition('Foo\Bar') should use getDefinition(Foo\Bar::class) when the string is a real class (compiler passes); a plain service id is left alone.
• NoServiceSetterCallRule — a config-closure ->call('setX', [service(...)]) should be a #[Required] setter; only a setXxx() fed a service() is reported (a container parameter or non-setter call stays).
• NoAutoconfiguredServiceTagRule — when the closure's defaults() uses autoconfigure(), a ->tag() that autoconfiguration already adds by interface (console.command, form.type, kernel.event_subscriber, security.voter, twig.extension, validator.constraint_validator) is redundant; only a tag with no attributes of its own is reported.

Each rule is registered in the matching set (doctrine-rules.neon, symfony-config-rules.neon, symfony-rules.neon), documented in the README, and covered by a RuleTestCase with report + skip fixtures.

Green locally: ECS, PHPStan, Rector, composer-dependency-analyser, neon-lint, full PHPUnit (378 tests).