docs: fix round 1 ride-along findings (F2-F7)

F2: test_christmastide_feria_slugs's 26 December assertions removed --
St Stephen/John/the Holy Innocents (RG 67-70) always outrank a Class4
Saturday candidate there, in every year, so the office can never
actually be observed on any day in the 26-28 December stretch. 3
January (no competing sanctoral entry, any year) used for the "-1-"
stretch demonstration instead, alongside the pre-existing 10 January
one.

F3: test_differential.ml's shared row type gains a subject field
(populated for colitur's own rows only; lectio's fixture has no such
column). C17's own predicate now also requires subject = "bvm" --
defence in depth against a future bug producing a white Class4
Saturday candidate some other way, particularly in Christmastide/
Paschaltide where colour alone could not catch it.

F4: Precedence_ef.band's entry-27 comment gains its RG 78 citation,
replacing "per the historical default that fills it".

F5: two report inaccuracies corrected -- band was already receiving a
real candidate 312,966 times pre-change (what was missing was its
identity, not its reality); the "Missae de S. Maria in sabbato" heading
quote was presented as "both scans, word for word" when both scans are
OCR-noisy there AND genuinely differ in abbreviation from each other --
corrected in temporal_ef.ml's own comment and the register alongside
the report.

F6: the colour rule gains a tighter citation chain -- RG 431(e) (the
Missal's own classification of this Mass as a "Missa votiva IV
classis... de B. Maria Virg.") -> RG 121(a) (votive Masses take the
colour of the feast-type they correspond to) -> RG 120(b) (BVM feasts
are white) -- reaching the same conclusion through the category (votive)
the Missal's own text actually places this Mass in, not by treating it
as a festum RG 91's own table structure says it is not.

F7: the oracle's real seasonal coverage recorded precisely in CLAUDE.md
and the register -- of 26 BVM-Saturday-office days in the 2026-2027
fixture only 17 are colour-discriminating; Time after Epiphany (5,015
observed days domain-wide) has zero oracle witnesses.

Full account in .superpowers/sdd/2026-08-12-colitur-rg16a/
bvm-saturday-report.md (local, gitignored).

1 files changed, 36 insertions, 5 deletions

diff --git a/CLAUDE.md b/CLAUDE.md
index 8cfa902..7875fbe 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -587,11 +587,16 @@ candidate is exactly one and already spoken for).
    IV-class Saturday" — decided entirely by the existing occurrence
    machinery (`band`'s own entry-27 branch already reads
    `rank = Class4 && weekday = Sat` unconditionally and only wins when
-   nothing outranks it), so **no change to `band`, `disposition` or
-   `admit` was needed** — rank stays Class4 either way, and none of the
-   three reads slug/colour/name to decide anything. Colour is white,
-   unconditionally (RG 120(b), not RG 119/127/128's seasonal rules — this
-   office is never "de Tempore" for colour). The slug is deliberately
+   nothing outranks it), so **`band` and `admit` needed no change** — rank
+   stays Class4 either way, and neither reads slug/colour/name to decide
+   anything (`disposition` DID need one, in a fix round — see below, RG
+   112(d)). Colour is white, unconditionally — the tighter chain, found in
+   a fix round (RG 431(e), the Missal's own classification of this exact
+   Mass as a "Missa votiva IV classis... de B. Maria Virg.", → RG 121(a),
+   votive Masses take the colour of the feast-type they "respondent" →
+   RG 120(b), BVM feasts are white — see below), not RG 120(b) alone
+   (a stretch: this Office is not itself a *festum*, RG 120(b)'s own
+   "de festis") and never RG 119/127/128's seasonal rules either way. The slug is deliberately
    UNCHANGED (reused from the ordinary `<season>-<week>-<weekday>` ferial
    fallback), the same precedent the Sacred Triduum (item 5) already set —
    identified structurally, never off the slug — and for a second, load-
@@ -636,6 +641,32 @@ candidate is exactly one and already spoken for).
    the mutation, proving RG 26's rank-keyed omission fires before any
    subject-keyed rule ever could.
 
+   **Fix round 1 (2026-08-13, coordinator review) — one blocking finding,
+   fixed.** RG 112(d) (Caput XVI): the Office, itself "de B. Maria Virg.",
+   excludes another commemoration invoking the SAME BVM's intercession —
+   violated live: `our-lady-of-mt-carmel` (16 July, `Commemoration_only`)
+   was wrongly commemorated on every 16-July-Saturday. Fixed in
+   `Precedence_ef.disposition` (`marian_slugs` ∪ `subject = Bvm` on both
+   sides of the collision — the disjunction matters, neither signal alone
+   identifies both real sides). Checked exhaustively, not merely for
+   Mt Carmel: only `Commemoration_only`-status Marian entries can ever
+   reach this live, and the ONLY other one, `our-lady-of-ransom` (24
+   September), is PROVABLY unreachable (forces the September Ember
+   Saturday every time, by construction). Re-measured: the original
+   75,853-day blast radius is unchanged in total, splitting into 74,633
+   `colour`-only + 1,220 `colour+comms`. Mutation-tested: exactly 3 tests
+   redden. Six further ride-along findings closed the same round: a
+   test pin corrected (26 December can never hold the office, St Stephen
+   always wins there — 3 January used instead); C17 gained a `subject`-
+   based identity guard; `band`'s own entry-27 comment gained its RG 78
+   citation; a tighter RG 431(e) → RG 121(a) → RG 120(b) colour chain
+   (conclusion unchanged); and the oracle's own coverage recorded
+   precisely — of 26 office days in the 2026-2027 fixture only 17 are
+   colour-discriminating, and **Time after Epiphany (5,015 observed days
+   domain-wide) has ZERO oracle witnesses**, resting on the scan and the
+   dedicated unit test alone. Full account:
+   `.superpowers/sdd/2026-08-12-colitur-rg16a/bvm-saturday-report.md`.
+
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