test(ingest): SQL connector + load-bearing + golden, detach-proven (I4)

New: test_ingest_sql.py (connector mechanics + typed rendering + dispatch), test_ingest_sql_loadbearing.py (SQL seams: typed-NULL, typed-REAL, navigability via unchanged okf), test_ingest_golden_sql.py + examples/ingest-golden-sql/ (byte-frozen sqlite golden; NULL->empty, 4200.0->4200.0 and escape discriminate a typed impl from naive ones). Updated: sql-source refusal test repointed to http (I6); manifest schema-breadth comment. Each new seam proven RED at its detach point.

Refs: shared/ingest-spec.md 11 golden + load-bearing table

tests/test_ingest_sql_loadbearing.py

@@ -0,0 +1,140 @@
+"""I4 load-bearing seams — the ``sql`` path end-to-end (ingest spec §11's detach-RED regime).
+
+The ``file`` seams (tests/test_ingest_loadbearing.py) are source-agnostic where they can be;
+these tests prove the SEAMS the ``sql`` source introduces — typed §5 rendering (the ``file``
+path is all-strings) and that a SQL-generated bundle flows through the SAME navigability and
+provenance machinery. Each test is built so the seam under test is the ONLY thing preventing
+the observable artifact (the Fase-2 green-but-dead trap).
+
+- NAVIGABILITY (§2/§11): a SQL-generated bundle is consumable by the UNCHANGED
+  ``okf.navigate_bundle``/``bundle_context`` — reachable via index cross-links, classified by
+  ``okf_type``, provenance riding through. RED when index linking is detached.
+- TYPED NULL (§5): SQL NULL renders as the empty string, NEVER ``"None"``. RED when the None
+  branch degrades to ``str(value)``.
+- TYPED REAL (§5): a REAL value keeps its shortest round-trip float form (4200.0 → ``4200.0``),
+  NEVER integer-coerced. RED when the float branch degrades to ``str(int(value))``.
+"""
+
+from __future__ import annotations
+
+import json
+import sqlite3
+from pathlib import Path
+from typing import Any
+
+from portfolio_optimiser import okf
+from portfolio_optimiser.ingest import materialize
+
+_INGESTED_AT = "2026-07-03T12:00:00Z"
+
+
+def _make_db(path: Path, script: str) -> Path:
+    conn = sqlite3.connect(path)
+    try:
+        conn.executescript(script)
+        conn.commit()
+    finally:
+        conn.close()
+    return path
+
+
+def _sql_manifest(tmp_path: Path, extractions: list[dict[str, Any]]) -> Path:
+    manifest = {
+        "manifest_version": 1,
+        "source": {"type": "sql", "id": "db", "connection_ref": "PROJ_DB"},
+        "bundle_summary": "SQL extracts from the project database.",
+        "extractions": extractions,
+    }
+    path = tmp_path / "manifest.json"
+    path.write_text(json.dumps(manifest), encoding="utf-8")
+    return path
+
+
+def test_sql_generated_bundle_is_navigable_via_unchanged_okf(
+    tmp_path: Path, monkeypatch: Any
+) -> None:
+    """LOAD-BEARING NAVIGABILITY: the SQL path produces a bundle the untouched OKF navigation
+    reaches through index cross-links (classified by okf_type, provenance preserved) and
+    ``bundle_context`` renders. RED when index linking is detached (file exists, unreachable)."""
+    db = _make_db(
+        tmp_path / "s.sqlite",
+        "CREATE TABLE costs (item TEXT, amount REAL);"
+        " INSERT INTO costs VALUES ('led', 120.0), ('hvac', 80.0);",
+    )
+    monkeypatch.setenv("PROJ_DB", str(db))
+    manifest = _sql_manifest(
+        tmp_path,
+        [
+            {
+                "id": "costs",
+                "title": "Project costs",
+                "query": "SELECT item, amount FROM costs ORDER BY item",
+                "okf_type": "dataset",
+                "max_rows": 100,
+            }
+        ],
+    )
+    bundle_dir = tmp_path / "bundle"
+    materialize(manifest, bundle_dir, ingested_at=_INGESTED_AT)
+
+    bundle = okf.navigate_bundle(str(bundle_dir))
+    by_name = {f.name: f for f in bundle.files}
+    assert "ingest-costs.md" in by_name
+    assert by_name["ingest-costs.md"].type == "dataset"
+    assert by_name["ingest-costs.md"].frontmatter["ingest_manifest"]  # provenance rides through
+    context = okf.bundle_context(bundle)
+    assert "Project costs" in context and "| hvac | 80.0 |" in context
+
+
+def test_sql_null_renders_as_empty_not_none(tmp_path: Path, monkeypatch: Any) -> None:
+    """LOAD-BEARING TYPED NULL: detaching the None branch to ``str(value)`` would render the
+    string ``None`` into the bundle; the empty cell is the ONLY correct §5 form."""
+    db = _make_db(
+        tmp_path / "s.sqlite",
+        "CREATE TABLE costs (item TEXT, note TEXT); INSERT INTO costs VALUES ('sensor', NULL);",
+    )
+    monkeypatch.setenv("PROJ_DB", str(db))
+    manifest = _sql_manifest(
+        tmp_path,
+        [
+            {
+                "id": "costs",
+                "title": "Project costs",
+                "query": "SELECT item, note FROM costs ORDER BY item",
+                "okf_type": "dataset",
+                "max_rows": 100,
+            }
+        ],
+    )
+    bundle_dir = tmp_path / "bundle"
+    materialize(manifest, bundle_dir, ingested_at=_INGESTED_AT)
+    body = (bundle_dir / "ingest-costs.md").read_text(encoding="utf-8")
+    assert "| sensor |  |" in body  # NULL → empty cell
+    assert "None" not in body  # RED if the None branch degrades to str()
+
+
+def test_sql_real_preserves_float_form(tmp_path: Path, monkeypatch: Any) -> None:
+    """LOAD-BEARING TYPED REAL: a REAL keeps its shortest round-trip float form; integer
+    coercion (``4200``) is the detach this test catches."""
+    db = _make_db(
+        tmp_path / "s.sqlite",
+        "CREATE TABLE costs (item TEXT, amount REAL); INSERT INTO costs VALUES ('kabel', 4200.0);",
+    )
+    monkeypatch.setenv("PROJ_DB", str(db))
+    manifest = _sql_manifest(
+        tmp_path,
+        [
+            {
+                "id": "costs",
+                "title": "Project costs",
+                "query": "SELECT item, amount FROM costs ORDER BY item",
+                "okf_type": "dataset",
+                "max_rows": 100,
+            }
+        ],
+    )
+    bundle_dir = tmp_path / "bundle"
+    materialize(manifest, bundle_dir, ingested_at=_INGESTED_AT)
+    body = (bundle_dir / "ingest-costs.md").read_text(encoding="utf-8")
+    assert "| kabel | 4200.0 |" in body  # float form preserved
+    assert "| kabel | 4200 |" not in body  # RED if integer-coerced