feat(examples): ship the §11 golden fixtures with byte-exact conformance

TDD step 8: three golden cases per the §11 format (manifest.json,
fixture/, ingested-at.txt, expected-bundle/) — ingest-golden-file and
ingest-golden-sql are the conformance MUSTs; ingest-golden-http
documents and exercises the optional extension against mock payloads.
The conformance test re-materializes each case into a fresh directory
and compares byte for byte; offline and credential-free (the sql
fixture is a committed database file, http never opens a socket).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QeqhJpYQyghASjiJo5EhGg

tests/test_golden.py

@@ -0,0 +1,64 @@
+"""Golden byte-for-byte conformance (ingest-spec §11) — load-bearing.
+
+Each golden case is re-materialized into a fresh directory and compared
+against its expected-bundle file by file, byte for byte. The test MUST fail
+when any byte of an expected bundle diverges. Offline, credential-free:
+the sql fixture is a committed database file, the http case runs against
+mock payloads served from its fixture directory.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from llm_ingestion_okf.materialize import materialize_bundle
+
+EXAMPLES = Path(__file__).parent.parent / "examples"
+INGESTED_AT_NAME = "ingested-at.txt"
+
+
+def fixture_backed_get(fixture_dir: Path) -> object:
+    """A mock transport serving fixture/{query path} — never a socket."""
+
+    def get(url: str, credential: str | None) -> str:
+        path = url.rsplit("/", 1)[-1]
+        return (fixture_dir / path).read_text(encoding="utf-8")
+
+    return get
+
+
+def materialize_case(case_dir: Path, out_dir: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    ingested_at = (case_dir / INGESTED_AT_NAME).read_text(encoding="utf-8").strip()
+    if case_dir.name.endswith("sql"):
+        monkeypatch.setenv("OKF_GOLDEN_SQL_DB", str(case_dir / "fixture" / "metrics.db"))
+        materialize_bundle(case_dir / "manifest.json", out_dir, ingested_at)
+    elif case_dir.name.endswith("http"):
+        materialize_bundle(
+            case_dir / "manifest.json",
+            out_dir,
+            ingested_at,
+            allow_network=True,
+            http_get=fixture_backed_get(case_dir / "fixture"),  # type: ignore[arg-type]
+        )
+    else:
+        materialize_bundle(case_dir / "manifest.json", out_dir, ingested_at)
+
+
+@pytest.mark.parametrize("case", ["ingest-golden-file", "ingest-golden-sql", "ingest-golden-http"])
+def test_golden_case_byte_for_byte(
+    case: str, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    case_dir = EXAMPLES / case
+    expected_dir = case_dir / "expected-bundle"
+    out_dir = tmp_path / "bundle"
+    materialize_case(case_dir, out_dir, monkeypatch)
+
+    expected_files = sorted(path.name for path in expected_dir.iterdir())
+    actual_files = sorted(path.name for path in out_dir.iterdir())
+    assert actual_files == expected_files
+    for name in expected_files:
+        assert (out_dir / name).read_bytes() == (expected_dir / name).read_bytes(), (
+            f"{case}/{name} diverges from the golden bytes"
+        )