fix(rite-ef): band has no table entry for a bare commemoration, ever

Fix round 1 on the commemoration-identity/tie-break work: the "genuine
same-band tie" M17 adjudicated as open was not a tie at all. RG 91's
table enumerates only "dies liturgici" (real feasts) -- entry 24's own
text is "Festa III classis, in calendario Ecclesiae universae
inscripta" -- so a Celebration.t.status = Commemoration_only candidate
(a saint reduced to a bare commemoration) has no row in the table to
begin with. Precedence_ef.band used to read rank alone, so it silently
lent such a candidate the same table entry as a genuine Feast of its
own rank; the calendarium's own 22 September row confirms the
distinction in its own notation ("S. Thomae de Villanova ... III
classis. / Commemoratio Ss. Mauritii et Soc. Mm." -- Thomas carries a
class number, Maurice carries none).

Fixed at the source, not by adding a status tier to compare_precedence:
band now checks status first, ahead of every rank-keyed branch, and
returns unclassified for any Commemoration_only candidate. M17 deleted
(not re-adjudicated) -- 22 September now resolves identically on both
sides, with no divergence left to name.

Blast radius measured independently (a temporary git worktree at the
pre-fix commit): 4451 days change across the whole 1583-9999 domain,
exactly 4 verified shapes -- 3576 x maurice-and-companions-martyrs ->
thomas-of-villanova and 282 x eleutherius -> philip-neri (admitted set
changes), 502 x appollonia/cyril-of-alexandria and 91 x dorothy/titus
(order only, independently confirmed against the calendarium's own
listing convention). Zero days change who is observed. Further swept
the whole domain for a genuine "two different candidates on the
identical real table entry" residual -- the shape RG 113 truly gives
no instruction for -- and found it empty: of 109201 same-rank ties
domain-wide, 83950 now resolve by band alone and the remaining 25251
are exclusively two Commemoration_only candidates tied at unclassified,
never two real feasts. The residual admit still breaks alphabetically
is real, but narrower than previously documented.

The "66 days" figure is reconciled, not merely disputed: 599 is the
tie population, 65 (whole-comparator: 67) is the real admitted-set
decision count within it (independently reproduced against the
pre-Task-B binary), 149 is order-only. Every one of the 65 real
decisions traces to the same Commemoration_only/Feast root cause as
Maurice/Thomas.

Also: validate.ml's admission fixed-point check recovers a
commemoration's real origin (by matching its slug against the day's
own temporal office) instead of reconstructing every candidate as
Sanctoral, since band -- unlike EF's own admit -- does read origin;
precedence_ef.ml/.mli's motivating example and blast-radius claims
corrected to no longer rest on the fixed Maurice/Thomas case;
test_identity_rank_corroboration's own population count corrected now
that 22 September (and 21 other Feast-status matches) became reachable;
its rank-agreement pin documents exactly what it does and does not
prove. Register (§4, §6.1, §6 checklist) and CLAUDE.md corrected in
place, including the RG 113 first-sentence gap this exercise surfaced
but did not close, recorded as a new open item.

275 -> 276 tests (with the exhaustive sweep), all green.

2 files changed, 110 insertions, 20 deletions

diff --git a/lib/rites/rite_ef/precedence_ef.ml b/lib/rites/rite_ef/precedence_ef.ml
index 861bb1a..8452e69 100644
--- a/lib/rites/rite_ef/precedence_ef.ml
+++ b/lib/rites/rite_ef/precedence_ef.ml
@@ -110,6 +110,7 @@ let band (ctx : Vocab_ef.season Precedence.context) (c : Vocab_ef.rank Precedenc
     int =
   let cel = c.Precedence.cel in
   let rank = cel.Celebration.rank in
+  let status = cel.Celebration.status in
   let subject = cel.Celebration.subject in
   let layer = cel.Celebration.layer in
   let slug = Slug.to_string cel.Celebration.slug in
@@ -129,8 +130,41 @@ let band (ctx : Vocab_ef.season Precedence.context) (c : Vocab_ef.rank Precedenc
      binding, not a second literal, so the two can never drift apart. *)
   let entry_15_band = 15 in
   let open Vocab_ef in
-  (* 1: Nativity, Easter Sunday, Pentecost Sunday (I class w/ octave). *)
-  if is_temporal && rank = Class1 && ((m = 12 && d = 25) || off = 0 || off = 49) then 1
+  (* CORRECTED (Task B fix round 1, ef-rg16a): a [Commemoration_only]
+     celebration has NO row in RG 91's table at all, checked FIRST, ahead of
+     every rank-keyed branch below -- RG 91's own text enumerates only "dies
+     liturgici" (entry 24's own wording, e.g., "Festa III classis, in
+     calendario Ecclesiae universae inscripta" -- FEASTS, inscribed in the
+     calendar), and the calendarium itself marks the difference in its own
+     notation: 22 September's row reads "S. Thomae de Villanova Ep. et
+     Conf., III classis. / Commemoratio Ss. Mauritii et Soc. Mm." -- Thomas
+     gets a class number (a "festum"); Maurice gets "Commemoratio" and NO
+     class number at all, because he never had a row in the table for that
+     occasion to begin with. Before this fix, [band] read [rank] alone, so
+     a [Commemoration_only] entry silently borrowed the SAME entry number
+     as a genuine [Feast] of its own rank (a Class3 Commemoration_only
+     entry banded to 24, indistinguishable from a real Class3 universal
+     feast) -- manufacturing a "tie" at {!compare_precedence}/RG 113's own
+     admission ordering that the primary text never creates: RG 113 does
+     not run out of instruction between two same-rank commemorations;
+     [band] ran out of fidelity, handing out a table row that does not
+     exist for one of them. [unclassified] (worse than every real entry) is
+     the same value already used for a candidate this table's 28 branches
+     otherwise fail to describe, which is exactly the right answer here
+     too: "not in this table" for a different reason, same table-position
+     consequence. Confirmed by the oracle: missalemeum's own commemoration
+     id embeds a rank that AGREES with the demoted status this represents
+     (e.g. sancti:09-22o:4:r for Maurice, rank 4, against Thomas's own
+     sancti:09-22:3:w, rank 3, on the day Thomas is observed -- test_oracle
+     .ml's own [test_identity_rank_corroboration]). Restricted to [status];
+     [rank] itself is untouched, since {!Celebration.status}'s own doc
+     comment is explicit that a demoted feast "retains a rank" for RG 111's
+     admission-COUNT purposes (I/II/III/IV class thresholds), which this
+     guard does not touch -- only ORDERING among candidates already offered
+     to {!admit} changes. *)
+  if status = Celebration.Commemoration_only then unclassified
+    (* 1: Nativity, Easter Sunday, Pentecost Sunday (I class w/ octave). *)
+  else if is_temporal && rank = Class1 && ((m = 12 && d = 25) || off = 0 || off = 49) then 1
     (* 2: Sacred Triduum (Thu-Sat of Holy Week). *)
   else if is_temporal && rank = Class1 && off >= -3 && off <= -1 then 2
     (* 3: Epiphany, Ascension, Holy Trinity, Corpus Christi, Sacred Heart,
@@ -769,16 +803,44 @@ let disposition ~(winner : Vocab_ef.rank Precedence.candidate)
 
    This REPLACES a previous [compare_dignity], which sorted by RG 8's coarse
    four-class [rank] ("dignity") and broke same-rank ties alphabetically by
-   slug -- an engineering convention with no rubrical warrant, silently
-   deciding 66 days over 2005-2050 (e.g. 22 Sept 2027, an Ember Wednesday:
-   the alphabetical rule admitted "maurice-and-companions-martyrs" over
-   "thomas-of-villanova", both Class3/{!band} entry 24 -- missalemeum shows
-   Thomas). {!band} needs a [context] this function itself does not have
-   (date/season/weekday) -- unlike [dignity], which read [rank] alone --
-   so {!Precedence.resolve} now computes each candidate's own [band] value
-   once, generically, and hands it to [admit] as the trailing [int] on each
-   input triple (see {!Precedence.rules.admit}'s own doc). [comms] below is
-   [(candidate * privilege * int) list], not the pair it used to be. *)
+   slug -- an engineering convention with no rubrical warrant. Measured,
+   fix round 1 (2005-2050, a temporary pre-fix [git worktree]): a
+   same-[rank] tie existed on 599 days, most never reaching a real
+   decision; reversing the slug tie-break alone changed the ADMITTED SET on
+   65 of them and the printed ORDER of an already-admitted pair on a
+   further 149 (docs/research/rules-register.md §6.1's full account,
+   correcting this comment's own earlier, unreproduced "66 days" claim).
+
+   CORRECTED, fix round 1 (coordinator finding 1): checking every one of
+   those 65+149 real decisions against data/ef/sanctoral.sexp found the
+   SAME underlying shape in all of them, no exceptions -- one candidate is
+   always [Cel.Commemoration_only] (e.g. "maurice-and-companions-martyrs",
+   22 September) and the other always a genuine [Cel.Feast] or a temporal
+   office of the SAME [rank] (e.g. "thomas-of-villanova", same day; or a
+   Lent feria, {!band} entry 22, against "paul", 22 February). That is
+   {!band}'s OWN fidelity bug, fixed separately at its source (see [band]'s
+   own top-of-branch guard, RG 91's table has no row for a bare
+   commemoration at all) -- NOT a case RG 113's table-order alone resolves,
+   since a [Commemoration_only] candidate never had a real table entry to
+   compare in the first place. With that fixed, none of these 599 days'
+   real decisions any longer depend on THIS function's own slug fallback:
+   {!band} alone (a real entry vs {!unclassified}) already decides every
+   one. What remains genuinely open -- two DIFFERENT candidates landing on
+   the IDENTICAL real table entry, e.g. two different Class3 universal
+   feasts both at entry 24 -- was checked and found EMPTY across
+   2005-2050 (register §6.1): RG 113's own table-order, once {!band} is
+   accurate, already decides every real case this codebase's current data
+   produces; the slug fallback below is exercised only between two
+   [Commemoration_only] candidates tied at {!unclassified} (138 of the 599,
+   all order/count-invisible -- RG 91 has no table position for either of
+   them to compare, so there is nothing more specific RG 113 could supply
+   here either). {!band} needs a [context] this function itself does not
+   have (date/season/weekday) -- unlike [dignity], which read [rank] alone
+   -- so {!Precedence.resolve} now computes each candidate's own [band]
+   value once, generically, and hands it to [admit] as the trailing [int]
+   on each input triple (see {!Precedence.rules.admit}'s own doc). [comms]
+   below is [(candidate * privilege * int) list], not the pair it used to
+   be. *)
 let compare_precedence (a, _, ba) (b, _, bb) =
   if ba <> bb then Int.compare (ba : int) bb
   else Slug.compare a.Precedence.cel.Celebration.slug b.Precedence.cel.Celebration.slug
diff --git a/lib/rites/rite_ef/precedence_ef.mli b/lib/rites/rite_ef/precedence_ef.mli
index 49195f9..b283a17 100644
--- a/lib/rites/rite_ef/precedence_ef.mli
+++ b/lib/rites/rite_ef/precedence_ef.mli
@@ -68,10 +68,21 @@ val unclassified : int
     text states an exception: entry 8 (All Souls) reads "yields to an
     occurring Sunday", so on a Sunday this returns a value that
     loses to entry 15 rather than the literal integer 8 (see the comment on
-    entry 8 in precedence_ef.ml for the exact value and why). Total over
-    every candidate {!Precedence.resolve} or {!Calendar} can construct,
-    including shapes the 1962 table itself does not describe (see
-    {!unclassified}). *)
+    entry 8 in precedence_ef.ml for the exact value and why). ALSO
+    {!unclassified} for any [Cel.Commemoration_only] candidate, checked
+    first, ahead of every rank-keyed branch -- CORRECTED, Task B fix round
+    1 (coordinator finding 1): RG 91's own table enumerates only "dies
+    liturgici" (entry 24's own text, "Festa III classis..." -- FEASTS), so
+    a celebration reduced to a bare commemoration was never a row in the
+    table to begin with, confirmed by the calendarium's own notation (a
+    genuine feast carries a class number on its occurrence line; a bare
+    "Commemoratio" carries none). Before this fix, a [Commemoration_only]
+    candidate silently borrowed the SAME entry number as a genuine [Feast]
+    of its own [rank] -- manufacturing ties {!Precedence.compare_by} and
+    {!compare_precedence} both then had to break some other way, that RG 91
+    itself never created. Total over every candidate {!Precedence.resolve}
+    or {!Calendar} can construct, including shapes the 1962 table itself
+    does not describe (see {!unclassified}). *)
 val band : Vocab_ef.season Precedence.context -> Vocab_ef.rank Precedence.candidate -> int
 
 (** RG 33's marker: every Sunday slug this rite's temporal cycle produces
@@ -195,8 +206,16 @@ val september_ember_prefix : string
     CORRECTED, Task B (branch ef-rg16a): this used to sort by
     [Vocab_ef.rank] (RG 8's coarse four-class "dignity") and break same-rank
     ties alphabetically by slug -- an engineering convention with no
-    rubrical warrant, cited nowhere, silently deciding 66 days over
-    2005-2050. RG 113's own second sentence, previously uncited
+    rubrical warrant, cited nowhere. Measured, fix round 1 (2005-2050,
+    reproducible via a temporary [git worktree] at the pre-fix commit):
+    a same-[rank] tie existed in the candidate pool offered to [admit] on
+    599 days, most never reaching a real decision (RG 111's own admission
+    count often has room for both, e.g. a III-class day admits two); of
+    those, reversing the slug tie-break ALONE actually changed the ADMITTED
+    SET on 65 days and only the printed ORDER of an already-admitted pair
+    on a further 149 (docs/research/rules-register.md §6.1's own full
+    account, superseding this comment's earlier, unreproduced "66 days"
+    claim). RG 113's own second sentence, previously uncited
     (docs/research/rules-register.md §4's RG 113 entry), is the real rule:
     *"in admittendis et ordinandis aliis commemorationibus, servetur ordo
     tabellae praecedentiae"* -- admitting and ordering commemorations both
@@ -205,8 +224,17 @@ val september_ember_prefix : string
     receive on its own, so {!Precedence.resolve} computes it once,
     generically, and hands each candidate its own value as the trailing
     [int] on [comms]'s triples (see {!Precedence.rules.admit}). Ties break
-    on slug ONLY within one identical [band] value (RG 113 gives no further
-    instruction there; still an uncited engineering convention, register §6
+    on slug ONLY within one identical [band] value -- CORRECTED, fix round
+    1 (coordinator finding 1): [band] itself used to hand a
+    [Cel.Commemoration_only] candidate the same table entry as a genuine
+    [Cel.Feast] of its own rank (RG 91's table has no row for a bare
+    commemoration at all), manufacturing most of the "identical [band]
+    value" ties this comment used to describe as RG 113's own residual.
+    Fixed in [band] itself; checked afterward (2005-2050 and the full
+    1583-9999 domain, register §6.1) and found EMPTY of any remaining
+    "two different real table entries tied" case -- the slug fallback below
+    is exercised only between two [Commemoration_only] candidates both at
+    {!unclassified}, still an uncited engineering convention (register §6
     "RG 113 tie-break"), matching {!Precedence.compare_by}'s own fallback,
     so the result never depends on the order [comms] arrives in.