This directory records architectural decisions that are hard to infer from the code alone: why a member lives where it lives, why an obvious refactoring was set aside, which constraint blocks a move.

• One decision per file, named NNNN-title-in-kebab-case.md, numbered sequentially and never renumbered.
• Status is one of Proposed, Accepted, Superseded by ADR-NNNN, Deprecated, and nothing else. An accepted ADR is never edited to reverse its decision, a new ADR supersedes it.
• Superseded by ADR-NNNN means the decision itself no longer holds. An ADR whose approach is merely no longer applied to new code stays Accepted for as long as its reasoning still explains part of the codebase. Record that shift in the body of the ADR, not in its status.
• Record the reasoning, not only the outcome. An ADR that states what was decided without stating what was rejected and why is of little use six months later.
• Line width 120, consistent with the rest of the repository.

0001 and 0002 record the two structural approaches and why the second replaces the first. 0003 applies them to the members still sitting in AbstractGraph.

0001 stays Accepted rather than superseded: plugins replace mixins for new code, but the mixin design still explains a large part of the current codebase, and its recorded costs are what justify the shift.