fix(artifact_pin): point at the canonical published HF dataset

The committed `priv/sakana_trinity/artifact_pin.json` shipped with
`repo_id: "your-org/trinity-coordinator-adapted-qwen3-0.6b"` as a
placeholder. That repo does not exist on the Hub, so every fresh-clone
invocation of `mix trinity.artifact.fetch` failed with `:unauthorized`
(the Hub returns 401 for unknown repos rather than 404). Surfaced by
the clean-room test on 2026-05-21:

    cd /tmp && git clone https://github.com/nshkrdotcom/trinity_coordinator
    cd trinity_coordinator
    XLA_TARGET=cuda12 mix deps.get && XLA_TARGET=cuda12 mix compile
    XLA_TARGET=cuda12 mix trinity.artifact.fetch
    → RuntimeError: trinity.artifact.fetch failed for manifest.json: :unauthorized

Repoint the pin at the canonical published dataset
`nshkrdotcom/trinity-coordinator-adapted-qwen3-0.6b` (published v1.0.0
on 2026-05-21). Sweep `guides/artifact_distribution.md` for the same
placeholder. Add a regression test that pins the committed
artifact_pin.json's `repo_id`, `revision`, and file count so a future
fork-and-republish cycle cannot reintroduce `your-org/`.

Gates: format / compile / test (297 / 0, 24 excluded) — all green.

Author: nshkrdotcom

guides/artifact_distribution.md

@@ -118,7 +118,7 @@ against silent regressions in the commit payload format.
 
 ```elixir
 artifact_dir = "priv/sakana_trinity/adapted_qwen3_0_6b_layer26"
-repo_id      = "your-org/trinity-coordinator-adapted-qwen3-0.6b"
+repo_id      = "nshkrdotcom/trinity-coordinator-adapted-qwen3-0.6b"
 token        = System.fetch_env!("HF_TOKEN")
 
 # 1. Create the dataset repo (idempotent with `exist_ok: true`).
@@ -195,7 +195,7 @@ points at the new revision:
 XLA_TARGET=cuda12 mix run build_support/build_artifact_pin.exs \
   --manifest priv/sakana_trinity/adapted_qwen3_0_6b_layer26/manifest.json \
   --bundle-dir priv/sakana_trinity/adapted_qwen3_0_6b_layer26 \
-  --repo-id your-org/trinity-coordinator-adapted-qwen3-0.6b \
+  --repo-id nshkrdotcom/trinity-coordinator-adapted-qwen3-0.6b \
   --revision v1.0.0 \
   --out priv/sakana_trinity/artifact_pin.json
 ```
@@ -210,7 +210,7 @@ has `:hf_hub` and `:jason` as dependencies, verify the public tag can
 resolve `manifest.json`:
 
 ```elixir
-repo_id = "your-org/trinity-coordinator-adapted-qwen3-0.6b"
+repo_id = "nshkrdotcom/trinity-coordinator-adapted-qwen3-0.6b"
 
 {:ok, path} =
   HfHub.Download.hf_hub_download(
@@ -256,7 +256,7 @@ under that.
 ```bash
 TARBALL=adapted_qwen3_0_6b_layer26-v1.0.0.tar.gz
 curl -L -o /tmp/$TARBALL \
-  https://github.com/your-org/trinity_coordinator/releases/download/v1.0.0-artifact-only/$TARBALL
+  https://github.com/nshkrdotcom/trinity_coordinator/releases/download/v1.0.0-artifact-only/$TARBALL
 
 echo "<expected-sha256>  /tmp/$TARBALL" | sha256sum -c -
 tar xzf /tmp/$TARBALL -C priv/sakana_trinity/

priv/sakana_trinity/artifact_pin.json

@@ -47,6 +47,6 @@
       "sha256": "6608a2669a921201c5fe81b2ddb938764663d63f5ec612a855ab7d5f6dc6966c"
     }
   ],
-  "repo_id": "your-org/trinity-coordinator-adapted-qwen3-0.6b",
+  "repo_id": "nshkrdotcom/trinity-coordinator-adapted-qwen3-0.6b",
   "manifest_sha256": "2a1476a4d2c7b66633232a564114dfb7ebe46f6bea624fc9ae9123678cafcbb9"
 }

test/trinity_coordinator/artifact_pin_test.exs

@@ -0,0 +1,49 @@
+defmodule TrinityCoordinator.ArtifactPinTest do
+  @moduledoc """
+  Pins the committed `priv/sakana_trinity/artifact_pin.json` against the
+  canonical published HF dataset so that `mix trinity.artifact.fetch`
+  works on a fresh clone without operator edits.
+
+  History: the pin file shipped with `repo_id: "your-org/..."` as a
+  placeholder; that crashed every fresh-clone onboarding flow with
+  `:unauthorized` because the `your-org/...` repo does not exist on
+  the Hub. The clean-room test on 2026-05-21 surfaced this.
+  """
+
+  use ExUnit.Case, async: true
+
+  alias TrinityCoordinator.ArtifactFetch
+
+  @committed_pin_path "priv/sakana_trinity/artifact_pin.json"
+
+  test "committed artifact_pin.json points at the canonical nshkrdotcom dataset" do
+    pin = ArtifactFetch.load_pin!(@committed_pin_path)
+
+    assert pin.repo_id == "nshkrdotcom/trinity-coordinator-adapted-qwen3-0.6b",
+           """
+           The committed artifact_pin.json must point at the published HF
+           dataset, not a placeholder. If you are forking the project, fork
+           the dataset too and update both pin.repo_id and the corresponding
+           SHA-256 values. Do NOT commit `your-org/` placeholders.
+           """
+  end
+
+  test "committed artifact_pin.json revision is a published tag" do
+    pin = ArtifactFetch.load_pin!(@committed_pin_path)
+
+    assert pin.revision == "v1.0.0",
+           "pin revision must match a tag published on the HF dataset"
+  end
+
+  test "committed artifact_pin.json lists exactly 11 files (manifest + router_head + 9 checkpoints)" do
+    pin = ArtifactFetch.load_pin!(@committed_pin_path)
+
+    assert length(pin.files) == 11,
+           "pin must enumerate every file in the artifact bundle (manifest.json, router_head.safetensors, 9 checkpoint safetensors)"
+
+    paths = Enum.map(pin.files, & &1.path)
+    assert "manifest.json" in paths
+    assert "router_head.safetensors" in paths
+    assert Enum.any?(paths, &String.starts_with?(&1, "checkpoints/"))
+  end
+end