Add SimpleScope PHPStan-free type resolution proof of concept

[TomasVotruba]

Why

First concrete step toward reducing PHPStan coupling in the codebase. PHPStan is currently a runtime dependency used across ~545 source files (type system, scope, reflection, phpdoc parser). This PR does not remove any of that - it proves a model for a dependency-free type layer on an isolated island, so we can evaluate the approach before touching real rules.

What

A standalone, PHPStan-free type-resolution layer:

• Rector\SimpleType\Contract\SimpleTypeInterface + concrete StringType, IntegerType, BooleanType, NullType, ArrayType, ObjectType, MixedType
• Rector\SimpleScope\SimpleScope - resolves an expression to a SimpleType (literals, new X, local variables)
• Rector\SimpleScope\SimpleScopeResolver - builds a scope from parameters and local assignments, in source order
• DemoObjectMethodCallRenameRector - a Tier-3 name-matcher rule that does its own type resolution with zero PHPStan usage in its logic

Scope and limits

• Nothing existing is changed; this is a self-contained island.
• Handles the local, syntactic cases (literals, new, typed params, local vars). Cross-file inference (method return types, property types, flow-sensitive unions) still needs real reflection and is intentionally out of scope - those return MixedType (safe no-op).
• Covered by a unit test for the resolver and fixture tests for the demo rule.

Passes composer complete-check and composer rector locally.