Add OntoDAG to Libraries

[petfold]

Adds OntoDAG to the Libraries section.

[OntoDAG](https://github.com/petfold/ontodag) - Category DAG on Swarm: canonical content-addressed roots, queries as intersections of subcategories, coordination-free merge between writers.

What it is. A Python library and odag CLI for a subsumption-only ontology: a multi-parent category DAG kept in transitively reduced form, queried by intersecting descendant cones. Categories can carry typed values (weight(3kg), time(2026-08-15)) whose order is computed exactly from the name, with no edges stored.

Swarm relation. Persistence is a first-class Swarm backend: odag set store swarm:NAME stores records through Bee's /bytes endpoint via recordstore (already listed here) and publishes the mutable latest-root in a signed Swarm feed, so a store can be followed and rehydrated from the network alone. Because the transitive reduction of a DAG is unique, equal knowledge yields the byte-identical root regardless of insertion order — which is what makes stores diffable, mergeable between writers without coordination, and verifiable (is_below answers ship with proofs against the root). Validated repeatedly against a live Bee light node on Gnosis mainnet, including scorched-earth rehydration purely via the feed.

Checklist

• One item, one PR.
• Public, not archived, BSD-3-Clause LICENSE, active (last push 2026-08-07).
• Link resolves; description is 141 characters, sentence case, matches this repository.
• Not already listed in README.md / archived.md, and no open PR or issue for it.

🤖 Generated with Claude Code

[crtahlin]

Approving — entry checks out.

• Format: 141 characters, sentence case, link resolves, not already listed.
• Repository: public, not archived, BSD-3-Clause, actively developed.
• Swarm relevance: recordstore is a base dependency rather than an optional extra, so Swarm persistence works on a bare install; signed-feed roots and odag swarm back that up.
• Description accuracy: "coordination-free merge between writers" is shipped — EagerOntoDAG.sync landed in 0.5.0. Worth noting docs/SWARM_DESIGN.md §5 is still headed "not yet implemented", which understates the current state; you may want to refresh it.
• Libraries is the right section, alongside recordstore and swarmfs.

I rebased the branch onto main and force-pushed, since #43 normalised the repository to LF line endings and landed between your submission and this review. That turned the diff from +152/−150 into the two lines actually being added; your authorship is unchanged. Apologies for touching your branch — it was our change that caused the conflict, and the fix was already verified locally.

[petfold]

Thanks for the thorough review — and no apology needed for the rebase, #43 was your side keeping the repo tidy and the diff is right.

You were correct about SWARM_DESIGN.md §5: the heading, its "Not started" paragraph and the "SwarmFeedPointer is a documented stub" line all predated the work, while an update block lower in the same section recorded that it had shipped — so reading top-down gave the opposite of the truth. Fixed in petfold/ontodag@1e6dacf: EagerOntoDAG.sync (0.5.0, delta-driven via RecordStore.diff since August, and on SparseOntoDAG too), the signed feed real since recordstore 0.4.0 and validated against a live Gnosis-mainnet node. What's genuinely still open is now stated as such — the tombstone / observed-remove decision (the shipped stance is grow-only) and the GSOC operation feed, which is optional transport on top of the fold rather than a prerequisite.