fix(k1 tax basis): odd cents of property basis run cumulatively (B-36, D-38)

The tax-basis K-1 shared each entry's built-in gain, property without a
basis, prepaid at book and property distributed among the members entry
by entry, every tied odd cent to the first member: three equal odd-cent
properties contributed 50/50 left the members three cents apart.

Apply D-38's rule (the closes' cumulative largest remainder, through
kernel::apportion_cumulative): tax_capital::RunningSplit keeps each
member's exact running share, rounds the running shares afresh to the
cent and hands out the change, so no member's running share is ever a
cent from exact and tied cents alternate. A negative running whole is
rounded as its magnitude, a zero one by the sign of the whole just
split, so a run of losses mirrors its gains part for part. Exact running
shares are taken to ten places before rounding: a sum of Decimal thirds
can sit a hair under its cent (the law found 399.93 as 399.9299...).

tax_capital::entry_parts runs the splits over every posted entry from
the books' first, in date order, whatever span is asked for, with one
count per set of members with a part in the entry: a member never takes
a cent of an entry they had no part in (Item L's capital contributed is
the basis of the property that member contributed), and the count never
restarts, since its weights are each entry's own amounts, not shares.
An entry's reversal takes its original's split back out of the count
(RunningSplit::unsplit), so an entry's cents are the same in every span
and next year's beginning is this year's ending. The K-1's per-entry
lines come from k1::entry_lines, which k1_detail now uses too.

The book property each member contributed in an entry stays split entry
by entry (each member's property must stay within their own credit);
B-36 says so.

Tests: tied_odd_cents_of_property_basis_run_cumulatively (fails on the
per-entry split: 665.86 / 665.83); a_member_outside_an_entry_never_
takes_its_cents (three members; fails with one count for all members),
an_entrys_odd_cent_is_the_same_in_every_span (a reversal across the
span's start; fails with the count carried span by span or the reversal
not taken out), the_split_runs_in_date_order (fails in posting order);
the law a_running_split_never_drifts_a_cent (5,000 cases: the
largest-remainder rounding of exact integer shares, ties to the first,
and the negated run mirrored; fails with ties to the later member or a
zero running whole rounded as a gain); unit tests for one split,
alternating ties, a member outside a split, the mirror at zero, unsplit
and the thirds case; bookspec example partnership-k1-tax-basis-odd-cents.
rules.md B-36, the handbook (tracing figures), STATUS, testing.md and
verification.md updated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

docs/spec/rules.md

@@ -2606,7 +2606,36 @@ book capital reconciles to tax capital:
 - Property contributed enters at its §723 basis (B-25): the member's
   share of the property's book value less their share of its built-in
   gain or loss at contribution, shared within the entry as its book value
-  is (B-13). Property contributed with no basis in the books (no
+  is (B-13). To the cent, these shares (and those of property without a
+  basis, of a prepaid at book, and of property distributed) run
+  cumulatively, D-38's rule (the owner, 2026-10-22): each member's
+  running share is the largest-remainder rounding of their exact running
+  share (ties to the member listed first), less what earlier entries
+  gave them, so it is never a cent from exact, and tied odd cents
+  alternate rather than all going to one member (three equal odd-cent
+  properties at 50/50 leave the members a cent apart, never three). How
+  the count runs differs from the closes': a close splits by the
+  members' shares among all the members, so its count starts afresh when
+  members or shares change; here each entry splits by its own amounts
+  (each member's property in it, or what each took) among the members
+  with a part in it. So there is one count for each set of members with
+  a part in an entry, and it never restarts: shares don't enter it, and
+  a member outside the set is never moved by it (Item L's capital
+  contributed is the basis of the property that member contributed, so
+  a member who contributed nothing in an entry takes none of its
+  cents). The count takes every posted entry from the books' first in
+  date order (ties in posting order), whatever span the worksheet is
+  for, and an entry's reversal takes the original's split back out of
+  the count, each member exactly their part: an entry's cents are the
+  same in every span it is in, and next year's beginning is this year's
+  ending to the cent. The book property each member contributed in an
+  entry (B-13's share of the entry's property among the members'
+  credits) stays split entry by entry, ties to the member listed first:
+  each member's property there must stay within their own credit in the
+  entry, which a running true-up could break; its odd cents arise only
+  in an entry part cash and part property whose credits don't divide
+  the property evenly.
+  Property contributed with no basis in the books (no
   registered asset linked to the entry holds a contribution basis for it)
   is open. Property contributed to a prepaid account (the balance
   account of a prepaid-expense schedule: a service contract the member
@@ -2638,7 +2667,14 @@ book capital reconciles to tax capital:
 
 **Enforced:** `ledger_core::tax_capital::tax_basis_capital`;
 `ledger-package` `k1_tax` (`k1-tax-basis-capital.csv` in the CPA
-package). **Checked:** `ledger-core` `tests/tax_capital.rs`;
+package); the odd cents, `ledger_core::tax_capital::RunningSplit` on
+`kernel::apportion_cumulative`. **Checked:** `ledger-core`
+`tests/tax_capital.rs` (`tied_odd_cents_of_property_basis_run_cumulatively`,
+`a_member_outside_an_entry_never_takes_its_cents`,
+`an_entrys_odd_cent_is_the_same_in_every_span`,
+`the_split_runs_in_date_order`, the law
+`a_running_split_never_drifts_a_cent`), the unit tests in
+`src/tax_capital.rs`, `bookspec/examples/partnership-k1-tax-basis-odd-cents.toml`;
 `ledger-package` `tests/package.rs`
 (`the_k1_worksheet_reports_tax_basis_capital`), `tests/p3_seams.rs`
 (`depreciation_is_one_figure_everywhere`,