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

examples/ingest-golden-sql/manifest.json

@@ -0,0 +1,18 @@
+{
+  "manifest_version": 1,
+  "source": {
+    "type": "sql",
+    "id": "golden-db",
+    "connection_ref": "OKF_GOLDEN_SQL_DB"
+  },
+  "bundle_summary": "Golden sql-source bundle: metrics extracted from a sqlite fixture database.",
+  "extractions": [
+    {
+      "id": "metrics",
+      "title": "Metrics",
+      "query": "SELECT id, name, value, comment FROM metrics ORDER BY id",
+      "okf_type": "dataset",
+      "max_rows": 10
+    }
+  ]
+}