Add configurable namespaces for generated classes

[Amoifr]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Issues	#1344
License	MIT

This PR is a proof of concept to support the discussion in #1344 — it is not intended to be merged as-is, but to serve as a concrete base for the ongoing reflection.

What it does

Adds an optional namespaces configuration to override the default namespace for generated classes:

maker:
    namespaces:
        entity: Domain\Entity
        controller: Application\Controller
        repository: Infrastructure\Repository

The directory is derived automatically from PSR-4 autoloading rules (no dir option needed, as @GromNaN suggested).

Design choices

• NamespaceType enum — replaces magic strings with a typed enum for all 5 configurable types (controller, command, entity, form, repository). Provides IDE autocompletion and prevents typos.
• Defaults centralized in the enum — each case knows its default via defaultNamespace(). The Generator merges user config on top of these defaults.
• Open map via scalarPrototype — the config accepts any key, not a fixed list. Users can override only what they need.
• Validation — each namespace value is validated via Validator::validateClassName().
• 10 makers updated — all makers using the 5 configurable types now go through $generator->getNamespace(NamespaceType::Entity) instead of hardcoded 'Entity\\'.
• No constructor injection needed — Generator is already available in generate(). The MakeController logic was moved from interact() to generate() to avoid adding a constructor dependency.

What's NOT in scope (possible follow-ups)

• CLI option (--namespace) for one-off overrides (mentioned by @GromNaN)
• Additional types beyond the initial 5 (listener, message, voter, etc.)