Expand lra-lean overlay for model towers and Blueprint

[wsollers]

What changed

• defines the exact LRA.VolumeII namespace hierarchy;
• forbids compatibility aliases and forwarding namespaces during renames;
• defines signature/laws/model architecture for configurable Z, Q, and R;
• sets canonical Z, canonical Q, and Dedekind R as the default tower;
• standardizes quotient compatibility and parameterized Peano iteration workflows;
• records the accepted sorry policy and verification-status distinction;
• adds Lean Blueprint, Docker documentation target, and GitHub Pages governance;
• adds Blueprint labels to the Volume II verification map.

This is the upstream source for the generated AGENTS.md overlay in lra-lean.