feat(ingest): I3 — D7-speil av ingest (filkatalog/CSV), bygget fra commons-spec alene

Speiler MAF I2 fra shared/ingest-spec.md alene: manifest → CSV-konnektor →
materialisert OKF-bundle, byte-identisk med den delte golden-fasiten.

- ingest.py: ManifestContract (pydantic, fail-fast, file-kilde, verdict-reservasjon
  §3, id-grammatikk, max_rows), CSV-konnektor (boundary-checked fail-closed),
  materialisering (§5-frontmatter eksakt rekkefølge, markdown-tabell m/ escaping,
  LF-only, SHA-256 manifest-stamp), index-generering (§6), replacement §3/§5.
- okf.py: _parse_index_entry — tolererer frontmatterløs index (method-spec §3:
  index rendres via body = summary, ikke som typet concept-fil). Golden var
  spec-konform; D7-okf var strengere enn standarden. Scoped: non-index concept-
  filer krever fortsatt type (honesty-test).
- examples/ingest-golden-file/: repo-lokal golden (byte-frossen kopi av I2s fasit).
- Speiltester (I2s load-bearing-sett, alle detach-bevist røde): golden byte-fasit
  + mutasjonskontroller · provenance/navigability/verdict-reservasjon/re-ingest-safety
  · kontrakt fail-fast/max_rows/boundary/kollisjon · spec-integritet §11.
- docs/2026-07-04-I3-brief.md: brief + de to operatør-avgjorte beslutningene.

Suite 239 passed uten nøkkel/nettverk (189 + 50 nye) · ruff + mypy --strict rene.

[skip-docs] README + docs/extending.md er bevisst utsatt til I7 per sesjonsplan
(programmet batcher ingest-doc der, avgrenset til det D7 faktisk har — CSV nå,
SQL/HTTP senere). Endringen er dokumentert i docs/2026-07-04-I3-brief.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017MM6BWb1hWmJZuXFZ7rjxT

src/portfolio_optimiser_claude/okf.py

@@ -18,6 +18,7 @@ from dataclasses import dataclass
 from pathlib import Path
 
 _INDEX_FILENAME = "index.md"
+_INDEX_TYPE = "index"
 _VERDICT_TYPE = "verdict"
 # (reference) the intra-bundle cross-link pattern, per §3 Step 1.
 _CROSSLINK_PATTERN = re.compile(r"\]\(([^)]+\.md)\)")
@@ -70,19 +71,40 @@ def parse_concept_file(path: Path) -> ConceptFile:
     )
 
 
+def _parse_index_entry(index_path: Path) -> ConceptFile:
+    """Parse the bundle entry point, tolerating a frontmatter-less index (§3 Step 1).
+
+    method-spec §3 Step 1 renders the index as "the index body (the summary)" and
+    treats every OTHER file as a "non-index concept file" (`## {type}: {title}`
+    section) — so the index is NOT a concept file, and it MAY omit frontmatter: a
+    generated index carrying only ``bundle_summary`` + cross-links (ingest spec §6,
+    frozen in the ingest golden) is valid. A frontmatter-ful index (the curated
+    convention, ``type: index``) still parses normally, its extra fields preserved.
+    When frontmatter is absent, the whole file is the body and ``type`` defaults to
+    ``index`` so downstream ``.type`` reads never raise.
+    """
+    text = index_path.read_text(encoding="utf-8")
+    lines = text.splitlines()
+    if lines and lines[0].strip() == "---":
+        return parse_concept_file(index_path)
+    return ConceptFile(path=index_path, frontmatter={"type": _INDEX_TYPE}, body=text.strip())
+
+
 def navigate_bundle(bundle_dir: Path) -> list[ConceptFile]:
     """Navigate from ``index.md`` — deterministic order: index first, links first-seen.
 
     Targets containing a path separator are out-of-bundle and skipped; resolution is
     boundary-checked against the bundle directory (fail-closed); broken links are
-    skipped, never raised. Repeated links are de-duplicated.
+    skipped, never raised. Repeated links are de-duplicated. The index entry point
+    may omit frontmatter (``_parse_index_entry``); non-index concept files still
+    require ``type``.
     """
     index_path = bundle_dir / _INDEX_FILENAME
     if not index_path.is_file():
         raise FileNotFoundError(
             f"bundle has no entry point: missing {_INDEX_FILENAME} in {bundle_dir}"
         )
-    index = parse_concept_file(index_path)
+    index = _parse_index_entry(index_path)
     bundle_root = bundle_dir.resolve()
     concepts = [index]
     seen = {_INDEX_FILENAME}