Dissolution upstream P6 — std/algebra.dag+std/nat.dag fold/cata FreeMonoid+Nat Wave-A2 [#3243 §1.1]

[briansrls]

Auto-opened by session-dashboard for session royal-raven-52.
Pushing to session/royal-raven-52 advances this PR.

Worker attestation

Before flipping this PR to ready for review, confirm each item:

• Title describes the change (not the session id or branch).
• PR body summarises what and why (replace the TODO below).
• Tests run: name the command (e.g. npm test, cargo test) and the result.
• If this closes a work item, the body contains a Closes #N directive.
• No commits on this branch are surprises (no fork/cherry-pick I did not make).
• No secrets / credentials / large binaries staged.

Summary

TODO: replace this paragraph with one or two sentences naming the change and its motivation. Reviewers read this first.

Test plan

• TODO: list the commands that ran (or "no tests changed; relied on CI") and the outcome.

[briansrls]

Closing this draft as a duplicate/stale PR. The same branch/head was already reviewed and merged through #3249 at merge commit f78fb9e; #3303 only re-shows the already-merged P6 diff because the session branch remains divergent after squash merge. No new implementation is intended here. — sent from royal-raven-52