eval: prove content-addressed catalog admission

[schickling-assistant]

Why

The Agent Spec catalog proposal needs portable product-conformance evidence,
not a green reference shim. This draft adds model-free cells that invoke the
real experimental st2 API from the companion prototype.

Tracks #37 and compoundingtech/st2#52.

What

Add the hierarchical agent-spec-lifecycle-catalog-* family:

1. prepare - exact-byte idempotent import without catalog visibility;
2. publish-cas - explicit staging, replay, manager fencing, ABA rejection,
   and no root movement;
3. root-atomicity - stale-root CAS, invalid-join rejection, atomic multi-seat
   admission, old/new-only reads, mixed-manager preservation, and corruption
   fail-closed.

The cells use ordinary team-less folder evals and shell/typed JSON judges. No
runner path, model seat, paid judge, or embedded catalog implementation was
added.

The VRS records typed-resource admission and public crash-boundary injection as
future discriminators; this first family does not claim those unsupported
properties and does not update the accepted AGENT-SPEC.md pin.

Exact prototype under test

• st2 PR: prototype: incubate content-addressed catalog admission st2#55
• st2 commit: 16ee7eb953508801a4603edd056ab32f28986601

Validation

Directly against that st2 binary:

• prepare: 5 PASS / 0 FAIL
• staging/CAS: 6 PASS / 0 FAIL
• root atomicity: 8 PASS / 0 FAIL

Free corpus checks:

• 77 KDL files parse;
• 46 maintained folder evals and 9 nested catalogs validate;
• preflight reachability, retired-surface scan, no-PII, catalog freshness,
  shell syntax, diff checks, and exact model-free harness exclusions pass.

The repository-wide harness-contract command still encounters the existing
synthetic Git identity policy rejection (seed@local versus the assistant
identity); the new three-cell exclusion coverage is independently exact.

Merge boundary

Keep this PR draft and do not promote the cells to accepted evidence until the
st2 API is accepted and the repository intentionally updates its global st2
pin. The current draft is executable incubation evidence.

Posted on behalf of @schickling

field	value
agent_name	co2-pine
agent_session_id	cdd15622-c01a-4731-bbfe-ab8cce0cad54
agent_tool	Codex CLI
agent_tool_version	0.145.0
agent_runtime	Codex CLI 0.145.0
agent_model	unknown
runtime_profile	/nix/store/ph8rlhdj25mg71v81jsfzy6dq4xpcs9m-coding-agent-runtime-profile/share/coding-agents/profile.json
skills_manifest	/nix/store/lsykz8x5481xrpbgk280xh3pypk1c5jy-agent-skills-corpus/share/agent-skills/manifest.json
worktree	evals/schickling-assistant/2026-07-29-content-addressed-catalog-evals
machine	dev3
tooling_profile	dotfiles@3649b53