docs(i4): brief + plan + golden fixture builder (I4)

Session brief (scope, non-goals, pinned SQL type/number decisions, verification) + TDD plan + build_fixture.py (regenerates the sqlite golden; the committed db bytes need not reproduce — the golden compares the derived bundle).

.claude/projects/2026-07-04-i4-ingest-sql-maf/build_fixture.py

@@ -0,0 +1,53 @@
+"""Build the I4 sql golden fixture: examples/ingest-golden-sql/fixture/portefolje.sqlite
++ ingested-at.txt.
+
+Regenerable; the committed db BYTES need not be reproduced bit-for-bit — the golden test
+compares the derived bundle (from db CONTENT via the manifest queries), not the db file.
+Parameterized inserts keep the backslash/pipe escape-probe values exact (no SQL string-literal
+surprises: 'c:\\temp' would be a tab if written as a Python literal). The data is chosen to
+discriminate a typed §5 implementation from naive ones — SQL NULL, an integral REAL (4200.0),
+non-integral REALs, and pipe/backslash text.
+"""
+
+from __future__ import annotations
+
+import sqlite3
+from pathlib import Path
+
+GOLDEN = Path(__file__).resolve().parents[3] / "examples" / "ingest-golden-sql"
+
+
+def main() -> None:
+    fixture = GOLDEN / "fixture"
+    fixture.mkdir(parents=True, exist_ok=True)
+    db = fixture / "portefolje.sqlite"
+    if db.exists():
+        db.unlink()
+    conn = sqlite3.connect(db)
+    try:
+        conn.execute("CREATE TABLE costs (id INTEGER, item TEXT, amount REAL, note TEXT)")
+        conn.executemany(
+            "INSERT INTO costs VALUES (?, ?, ?, ?)",
+            [
+                (1, "LED-armatur", 1200.5, "godkjent"),
+                (2, "sensor", 89.9, None),  # NULL → empty cell (discriminator)
+                (3, "kabel", 4200.0, "rest"),  # integral REAL → "4200.0", not "4200"
+            ],
+        )
+        conn.execute("CREATE TABLE meta (k TEXT, v TEXT)")
+        conn.executemany(
+            "INSERT INTO meta VALUES (?, ?)",
+            [
+                ("owner", "anlegg | drift"),  # pipe → escaped \|
+                ("path", "c:\\temp"),  # backslash → escaped \\
+            ],
+        )
+        conn.commit()
+    finally:
+        conn.close()
+    (GOLDEN / "ingested-at.txt").write_bytes(b"2026-07-04T12:00:00Z\n")
+    print(f"built {db} ({db.stat().st_size} bytes) + ingested-at.txt")
+
+
+if __name__ == "__main__":
+    main()