P3: odd cents split the same running way everywhere (defect 17, D-38)

Members' shares of earnings are split cumulatively by largest remainder in
the closes, the members' equity statement, the K-1 worksheet and the
viewer, so a member's capital on a given day never moves by a cent when its
month is later closed. Old closes replay as they were; the first P3 close
carries any true-up. Feature members_cumulative. Kani and Lean proofs of
the bounded drift; bookspec examples.

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

crates/ledger-store/tests/fixtures/old-books-writer/Cargo.toml

@@ -9,6 +9,9 @@
 #   cargo run --bin older -- OUT      (x_older_rules, with its JournalWriter)
 #   cargo run --bin expect -- OUT     (expected.json beside each journal)
 # and copy each journal.jsonl, blobs/ and expected.json into old-books/.
+# x_member_closes was written later, the same way, by main 00226a4c
+# (2026-10-20, before P3's odd cent): `cargo run --bin members -- OUT`
+# (members closes under every rounding rule main wrote; P3 review R-2).
 [package]
 name = "writer"
 version = "0.1.0"
@@ -22,3 +25,5 @@ rust_decimal = "=1.43.0"
 serde_json = "1"
 
 [workspace]
+# main's crates (wb-main) keep their own workspace.
+exclude = ["wb-main"]