12C: Hand every pass the registry it reads, instead of a static call

[nikolaystrikhar]

What: adds Registry_Reader, moves the registration buffer off Absorber, gives Conflict\Detector and Loader one as a constructor argument, and binds it in Provider.

Usage:

$loader = new Loader( new Registry_Reader( $registrar ), $notices );

$loader->load_all();

Why this way:

The facade sat both above its collaborators and below them. It boots them, and they reached Absorber::all() to walk the registry — an edge pointing back up that no double could stand in for and no test could avoid standing up. Absorber::register() now pushes into the reader and Absorber::all() delegates to it; nothing but Absorber names Absorber.

A pass is complete the moment it is built. Holding its registrar means it no longer needs the container to read, so an unbuildable Registrar_Interface fails while the pass is being built — where an unbuildable Queue_Interface has always failed.

The buffer stays static, because register() is a static call a host makes at plugin-file scope, before there is a container to resolve a registrar from. What changed is only which class pays for that.

Over the source-file cap, at five. Registry_Reader is the seam; Absorber, Detector, Loader and Provider are the four callers it cannot land without.

[d4mation]

Took a bit to understand why Registry_Reader is named the way it is, but once I realized it was to read the Registrar object in the same buffered way as before it made more sense :)