feat(okf-v0.2): D5 — the v0.2 golden fixture, with okf_version in root frontmatter

Placement settled by catalog's own reading of upstream at the pinned commit
3fcbb9f: SS8:509-510 and SS12:773-775 both put `okf_version` in a bundle-root
`index.md` frontmatter block, and SS12 calls it the only place frontmatter is
permitted in an index. Catalog's spec says the opposite about the same file;
that divergence is theirs against upstream, and we conform to upstream.

The value never touches a profile. `OKF_V0_2.index.root_frontmatter` names the
key; the caller supplies the value through a new keyword-only
`root_frontmatter_values` mapping. That keeps V4/V-A5 intact - `okf_version`'s
value tracks the upstream Google version and belongs to catalog (E1), so a
constant here would claim a decision we do not own and would have to be chased
on every upstream release. In the fixture the value is fixture DATA
(`okf-version.txt`), not a literal in our source.

Ordering comes from the policy, not the caller's mapping: a dict preserves
insertion order, so two callers passing the same keys would otherwise emit
different bytes. A key the policy does not name is refused fail-fast, before
any disk mutation. Omitting the argument emits no block at all - SS12 is a MAY
and none of upstream's four reference bundles declares the key.

The block is written only when the index is CREATED, so a re-run into an
existing bundle stays byte-identical (A-E5).

Raw-byte assertions rather than parsed ones, on the committed fixture as well
as on fresh runs: catalog measured that a quoted value fails their shape regex
with exit 1 and that a BOM hides the marker while still exiting 0.
`yaml.safe_load` returns "0.2" either way and strips a BOM first, so a parsed
assertion masks exactly those two defects. Asserting the frozen fixture catches
what a self-comparison cannot - regenerating from a broken emitter moves both
sides together.

A-E6 is now placement-explicit (promised catalog in 99cf987), and separates the
two byte properties: BOM-free is a property of the file, unquoted is a property
of CATALOG'S GATE and not of OKF v0.2 - upstream's own SS12 example is quoted,
so their gate rejects the spec's canonical form.

README gains the upstream-version section it was missing; CLAUDE.md gains the
mechanism behind "no profile hard-codes an upstream version": a profile names a
key, a caller owns its value.

550 -> 559 tests. test_profile_threading's `OKF_V0_2.index is DEFAULT.index`
assertion is replaced rather than deleted: object identity was a proxy for "the
shipped profiles differ in no NAME-bearing field", which is what makes the
synthetic test profile necessary, so the guard now asserts that directly.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013dgkSPjkLpACjMayd9R5jx

docs/plan/okf-v0.2-alignment.md

@@ -752,24 +752,45 @@ output is the baseline. Materialize it twice with the *same* explicit
   undecided: whether a `DEFAULT`-written bundle may be re-run **in place** under
   `OKF_V0_2` — i.e. whether the predicate accepts both the v0.1 stamp and the
   v0.2 form. That is a D2 requirement question standing with the operator.
-- **A-E6** The root `index.md` declares `okf_version: 0.2` — **unquoted**, and
-  the file carries **no UTF-8 BOM**. Both are load-bearing, not stylistic:
-  catalog measured that a quoted value fails their shape regex `exit 1`, and
-  that a BOM makes the marker invisible to them while still exiting `0`. The
-  emitter renders values verbatim, so this is a property of the value we hand
-  it. Verifying the raw bytes here is part of the expectation.
+- **A-E6** The root `index.md` declares `okf_version: 0.2` in a **frontmatter
+  block opening the file** — the first bytes are `---\nokf_version: 0.2\n---\n\n`
+  — with the value **unquoted** and **no UTF-8 BOM**.
 
-  **What A-E6 does not yet say is WHERE**, and as of 2026-07-26 that silence is
-  load-bearing rather than cosmetic. Upstream §12 puts `okf_version` in the root
-  `index.md`'s frontmatter block; catalog's own spec (`:55`, `:95`) says an
-  `index.md` has no frontmatter and carries the marker as a body line. A bundle
-  conforming to one is non-conformant against the other. Catalog verifies against
-  upstream before touching their §6, and D5 is not frozen until they have. Their
-  gate cannot settle it either way — the shape regex is unanchored and matches in
-  both places — so a green TEST B measures the value, never the placement. A-E6
-  becomes placement-explicit before the pilot receives it, whichever way the
-  choice lands; an expectation that does not state what it expects is the defect
-  class this very expectation is named after.
+  **PLACEMENT — settled 2026-07-31, frontmatter.** Catalog read upstream
+  themselves at the pinned commit `3fcbb9f` and reported §8:509-510 ("Index files
+  contain no frontmatter, with one exception: a bundle-root `index.md` MAY carry
+  an `okf_version` key") and §12:773-775 (declared "in a bundle-root `index.md`
+  frontmatter block (the only place frontmatter is permitted in an `index.md`)").
+  Their own spec (`:55`, `:95`) says the opposite about the same file; the
+  divergence is real, it is **theirs against upstream**, and its resolution is
+  their operator's. We conform to upstream. D5 is frozen on that.
+
+  **The two byte properties are expectations about DIFFERENT things, and A-E6
+  must not conflate them** — doing so would be this expectation's own defect
+  class:
+
+  - **Unquoted** is a property of **catalog's gate**, NOT of OKF v0.2. Their
+    shape regex `/^\d+(\.\d+)*$/` reads the quotes as part of the value and
+    exits 1. Upstream's §12:773 is the only line in the whole spec showing the
+    key *with* a value, and it shows it **quoted** — so their gate rejects
+    upstream's own canonical example. That is catalog's defect to resolve, not
+    ours to work around, but while it stands, an unquoted value is what passes.
+    We emit unquoted, and A-E6 expects unquoted **of catalog's gate**.
+  - **BOM-free** is a property of the file we emit, full stop. A BOM makes the
+    marker invisible to their gate *while still exiting 0* — a failure that
+    reports success.
+
+  Both are asserted on **raw bytes**, never on a parsed value: `yaml.safe_load`
+  returns `"0.2"` whether or not it was quoted and strips a BOM before any caller
+  sees it, so a parsed assertion masks precisely these two defects.
+
+  **A green TEST B does not confirm the placement, and a red one does not
+  identify it.** The shape regex is unanchored, so it matches in the frontmatter
+  block and in a body line alike — green measures the value, never the position.
+  Catalog sharpened the other direction on 2026-07-31: moving the marker into
+  frontmatter *with* quoting, as §12 literally shows it, also yields FAIL. So a
+  red run cannot distinguish "wrong quoting" from "wrong placement". Read TEST B
+  as a statement about the value's shape only, in both directions.
 
 **What would surprise us — report immediately:** any diff outside the frontmatter
 block (the profile seam leaks); `at` differing from the `ingested_at` they passed
@@ -1096,7 +1117,17 @@ everything after. **Done 2026-07-26** (`1215f98`, `7bc366b`).
 6. **D5** — the v0.2 golden fixture, generated by the code. `okf_version: 0.2`
    is declared only here, once 1–5 are green (conform first, claim after).
    **Unquoted** — the quoted form written here previously contradicted A-E6 and
-   is exactly what catalog measured as `exit 1`.
+   is exactly what catalog measured as `exit 1`. **Done 2026-07-31** (559
+   tests): `examples/ingest-golden-okf-v0-2/`, emitted by the code and frozen
+   byte-exact, with the marker in the root `index.md`'s frontmatter block per
+   upstream §8/§12. The value reaches the emitter as
+   `materialize_bundle(..., root_frontmatter_values={"okf_version": ...})` —
+   keyword-only, defaulting to none, so every existing call site is untouched.
+   The profile names the key (`OKF_V0_2.index.root_frontmatter`) and never
+   carries the value, which is V4/V-A5 held intact: the value is catalog's (E1),
+   and in the fixture it is fixture DATA (`okf-version.txt`), not a constant in
+   our source. Offering a key the policy does not name is refused fail-fast
+   before any disk mutation.
 7. **P1** — read-only sweep over real pilot bundles. Cheap, zero-risk, and the
    first point where a finding can come from outside our own assumptions.
 8. **Pre-release tag `v0.5.0a1`**, then **P2** (producer) and **P3** (gate).