feat(cli,consume): the first span, and the fusion that punished fine-graining

Round 6 left two things behind: a measured coverage hole with the repair built
but not the number to move it, and a retrieval regression that kept two
spreadsheet rules off the default. Both are measured; four defaults move.

THE HOLE IS BIGGER THAN THE RULE BUILT FOR IT. Measured over the 39-document
corpus, the pre-move default left 207 435 characters -- 11.92 % -- in no
segment: 163 804 above the first entry, 26 041 between entries, 17 590 after
the last. `--first-span-from-zero` closes the first part entirely, 79 % of the
whole, leaving 43 631 (2.51 %) over 8 of 32 documents. It adds no boundary and
the K2 concept count is identical with and without it (425 = 425); hit@8 holds
[1,1,1,1,1,-] under both tie-breaks and the 12-position reference does not move
one cell.

THE RANKER WAS PUNISHING FINE-GRAINING FOR BEING FINE-GRAINED. Round 6 held
`--sheet-section-rows --keep-table-heading` back because on a bundle built with
them row 1 fell rank 1 -> 2, and ruled out the document prior because its rank
over 39 DOCUMENTS was 1 on both bundles. RRF reads a rank over CONCEPTS:
splitting the gold document 1 -> 12 puts its own twelve concepts in that
signal's whole top tie group, so the one leading the body signal takes position
11, contributing 1/71 where the undivided concept contributed 1/61. A signal
that scored them all EQUALLY still emitted twelve ranks, ordered by concept_id,
and the fusion read alphabetical order as a measurement.

AND THE REPAIR WAS ALREADY IN THE TREE, OFF FOR A COST THAT HAD BEEN REMOVED.
`--tie-shared-rank` shipped off 2026-09-08 because hit@8 fell 5 of 6 to 4 of 6.
Swept over 2 prior exponents x 3 bundles x 6 rows: that fall exists only at
DOCUMENT_PRIOR_EXPONENT 1.0. Round 6 moved the exponent to 0.5 for an unrelated
reason and correctly reported it moved no hit@8 row -- nobody measured the
pair. A flag's "off by measurement" is a measurement of a CONFIGURATION, not a
property of the flag.

Shipped, each with an explicit opt-out and both directions measured rather than
asserted: --no-first-span-from-zero --no-sheet-section-rows
--no-keep-table-heading reproduces the previous bundle byte for byte (diff -rq,
0 differences), and the no-flag build equals the explicit-flag build.
--no-tie-shared-rank reproduces the previous excerpt order -- the one change
here that alters a payload with no bundle changing.

K2 default: 436 concepts / 832 files, digest 8dff8a8e6c15d2f7..., hit@8 5 of 6
ranks [1,1,1,1,1,-]. The pin now holds its own known-negative on those bytes:
read with --no-tie-shared-rank the same bundle gives [2,1,1,1,1,-], so the
green assertion names its cause. Consumer cost is a re-run: 425/810 -> 436/832
on the reference corpus, 15/30 -> 26/52 on a five-document folder.

pptx and md measured end to end for the first time, on two hand-built
documents: md recovers 3 of 4 declared headings, pptx segments per slide only
where the converter recognised a title placeholder. A converter attribute leaks
into titles ({#slide-N}, {#sheet-1}) on 2 of 810 K2 files and 1 of 30 on a
five-document folder -- not fixed, because a filename is reduced from its title
and the fix renames concept ids a consumer has cited.

Suite 1486 (1478 before), ruff and mypy --strict clean over 21 files.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/llm_ingestion_okf/consume.py

@@ -1063,6 +1063,29 @@ def document_scores(
 #: fusion is invariant to any monotone transform of the individual signals.
 RRF_K = 60
 
+#: Whether concepts a signal scores EQUALLY share that group's first rank
+#: instead of being ordered inside it by `concept_id`. ON since 2026-09-10.
+#:
+#: WHY IT MOVED. It shipped OFF on 2026-09-08 on a measurement -- hit@8 over
+#: the six published questions fell 5 of 6 to 4 of 6 on the 629-concept bundle.
+#: Round 7 re-measured that fall and it is CONDITIONAL on the document prior
+#: being a sum: swept over `DOCUMENT_PRIOR_EXPONENT` x 3 bundles x 6 rows, the
+#: lost row is lost at exponent 1.0 and held at 0.5. Round 6 moved that
+#: exponent to 0.5 for an unrelated reason and nobody re-measured the pair, so
+#: a rule was left off by a cost that had already been removed.
+#:
+#: WHAT IT BUYS. It is the repair for the defect that kept `--sheet-section-rows
+#: --keep-table-heading` off the build default: a document split from 1 concept
+#: into 12 puts its own 12 concepts in the prior signal's whole top tie group,
+#: so the concept leading the body signal takes prior position 11 rather than
+#: 1 and the document loses fused rank 1 to a single-concept competitor that
+#: leads nothing. Fine-graining was being punished for being fine-grained.
+#:
+#: Measured at exponent 0.5 on three bundles, ranks per row: `[1, 1, 1, 1, 1,
+#: None]` on all three with it on, against `[2, 1, 1, 1, 1, None]` on the split
+#: bundle with it off. Opt-out `--no-tie-shared-rank`.
+DEFAULT_TIE_SHARED_RANK = True
+
 
 def concept_scores(
     concepts: Sequence[Concept],
@@ -1072,7 +1095,7 @@ def concept_scores(
     cost_vocabulary: bool = False,
     weights: Mapping[str, float] | None = None,
     lookup: bool = True,
-    tie_shared_rank: bool = False,
+    tie_shared_rank: bool = DEFAULT_TIE_SHARED_RANK,
 ) -> list[tuple[Concept, float, int]]:
     """Every concept, ordered best first, fused from three signals by RRF.
 
@@ -1464,7 +1487,7 @@ def build_payload(
     cost_vocabulary: bool = False,
     reserve_top_rank: bool = False,
     rarity_weight: bool = False,
-    tie_shared_rank: bool = False,
+    tie_shared_rank: bool = DEFAULT_TIE_SHARED_RANK,
     withheld_titles: bool = False,
 ) -> dict[str, object]:
     """One bundle plus one question, cut to one contract-conformant payload.
@@ -1666,13 +1689,22 @@ def parse_args(argv: list[str] | None) -> argparse.Namespace:
     parser.add_argument(
         "--tie-shared-rank",
         action="store_true",
+        default=DEFAULT_TIE_SHARED_RANK,
         help=(
             "let concepts a signal scores EQUALLY share that score group's "
             "first rank, so a signal that separates nothing contributes the "
-            "same constant to each of them instead of ordering them by id. OFF "
-            "by default. See docs/2026-09-08-rangeringsbom-sammensatte-ord.md"
+            "same constant to each of them instead of ordering them by id. ON "
+            "since 2026-09-10. See docs/2026-09-08-rangeringsbom-sammensatte-ord.md "
+            "for the rule and docs/2026-09-10-k3-runde7-forste-spenn-og-rangeringen.md "
+            "for why its published cost no longer holds"
         ),
     )
+    parser.add_argument(
+        "--no-tie-shared-rank",
+        action="store_false",
+        dest="tie_shared_rank",
+        help="The rule's explicit opt-out, reproducing the pre-2026-09-10 order",
+    )
     parser.add_argument(
         "--withheld-titles",
         action="store_true",