feat(arap)!: documents read their figures from standing lines; control accounts

refuse hand entries (P4b S1, part A)

Plan P4b (D-45), slice S1, the engine half: rules.md B-38.

- ledger-core: every receivables or payables line carries its document
  (Ledger.line_docs: DocRef, Movement, DocTag), written by the document
  commands in the step that posts it, derived on replay from the existing
  document events (the role's account as it stood then; payments by the
  ordinal rule), copied onto a reversal's mirror. Ledger::stands_on;
  doc_state / invoice_state / bill_state (total, paid, outstanding,
  status Open/Partial/Paid/WrittenOff/Void, overdue days) as of any day;
  ar_aging / ap_aging read them, so reversed payments and voids are right.
  The control guard (add_line, add_line_fx, post_entry,
  register_recurring) refuses untagged lines on receivables/payables,
  exempting a reversal's mirror of a legacy line; replay never refuses.
  Bounds (kernel::running_bounds, bounds_kept) on payments and reversals;
  a document reversal never dated before its entry; deposit/payer accounts
  must be cash-like and hold no role. New API: receive_payment_with /
  pay_bill_with (PaymentDetails: instrument, reference), void_document /
  check_void_document, control_check, payments_recorded,
  standing_payments, replay_reverse_entry. Invoice.amount_paid/status
  remain only as derived caches for the MCP layer until part B.
  cashflow bill_splits reads payments from the tags.
- ledger-store: journal feature document_standing (D-39 gated) for a
  payment accepted only because an earlier one was reversed;
  receive_payment_with / pay_bill_with (instrument journaled as
  entry.instrument_set, reference in the description), void_document;
  replay uses replay_reverse_entry; schema 15 drops the projection's
  amount_paid/status. Fixture p4-arap-before + golden figures written by
  the version before S1, adjudicated in arap_standing.rs.
- ledger-gui: party card, cash "coming up" and company owed totals read
  doc_state as of today (late from the derived state).
- Lean Documents.lean (control_agrees and friends); Kani
  bounds_check_matches_definition,
bounds_kept_is_the_definition_on_books_in_bounds;
  rules B-38, B-18/B-23 amended; bookspec `older = true` for legacy hand
  lines; tests that hand-post to 1200/2000 post as replay or renumbered.

Review fixes (both reviews of part A):
- control_role_of guards only an account the role is assigned to or one
  holding its documents' lines (a chart's own 1200 Equipment or card at
  2000 is free until a document posts there); payment accounts check
  other roles by holds_role (type-checked). The MCP tests that failed on
  the guard (oracle_mcp, spec_projects) pass unchanged.
- standing_payments leaves out reversals (sorted, deduped); replayed
  tags match the movement's side; payments_recorded counts every payment
  event (tagged or not, Ledger.payment_events) and refuses overflow.
- The record caches settled (paid + discounted + written off) and owed
  (Invoice/Bill.owed, never serialized): a void never reads as paid.
- assign_role: receivables/payables refuse moving onto an account with
  untagged lines (RoleAccountHasHandLines) and, on their control account
  holding a balance, say DocumentRoleHoldsBalance (no hand entry named);
  B-23 reworded. The reversal-mirror exemption only takes a hand line
  off (even chain depth); putting it back is refused.
- DocStatus Overpaid and Unattached; aging leaves out credit balances;
  ControlCheck.attention lists out-of-bounds and unattached documents.
- stands_on counts a chain in order; indexes (doc_index, doc_accounts,
  order_pos, reversed_by) keep the derived figures linear.
- Viewer reads a post-dated document as of its own date; one state per
  row. bounds_kept's side-crossing documented as intended.
- Tests: ten new spec_documents scenarios, stronger proptests, store
  proptest arap_props (live = replay = snapshot at every date, closed
  months), fuzz ops void/payments with details, a GUI post-dated test;
  Lean Step.assign / Step.release with unattached_zero kept; model
  limits stated in docs/testing.md and B-38.
Review fixes (CPA and engineering lenses): only an assigned role's
account or one holding document lines is a control account (a chart's
own 1200 asset stays free); a role can't move onto untagged lines or off
document lines (Lean Step.assign); a void's cache never reads as paid;
no Decimal sum panics; per-document indexes keep figures linear; a
replayed tag matches its side; the feature gate counts payment events;
a payment's reversal is never listed as standing; an overpaid document
has its own status; the viewer keeps post-dated documents.

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

README.md

@@ -251,6 +251,11 @@ the side gives the direction.
 - `instrument` on an event: the payment method (a `setup.instruments`
   label) the entry was paid with. Neither `parties` nor `instrument` on a
   reversal, which takes its original's, nor on a command.
+- `older = true` on an entry (`lines`): the entry as an earlier version
+  could write it, which this version's commands refuse: a line by hand
+  on a receivables or payables account, where only an invoice, a bill or
+  their payments post now (rules.md B-38, the control guard). Books that
+  hold one must still read right, so the books take it as replay does.
 - `close = { start, to, rounding? }` as an event: closes the period from
   `start` through the event's `date` (rules.md B-11, B-13), `to`
   `"members"` (split by share, in the order listed) or

examples/1099-money-from-a-payee-is-netted-only-as-a-refund.toml

@@ -63,6 +63,7 @@ lines = [
 [[events]]
 date = "2026-03-01"
 description = "Dana Studio pays the company's invoice"
+older = true
 payee = "Dana Studio"
 lines = [
   { account = "1000", side = "debit", amount = "450.00" },

examples/p3-party-signs-and-reversals.toml

@@ -176,6 +176,7 @@ lines = [
 [[events]]
 date = "2026-10-20"
 description = "Bill"
+older = true
 parties = [{ party = "Northwind Filings" }]
 lines = [
   { account = "6000", side = "debit", amount = "80.00" },
@@ -192,6 +193,7 @@ reverses = 7
 [[events]]
 date = "2026-10-20"
 description = "Invoice"
+older = true
 parties = [{ party = "Riley Chen" }]
 lines = [
   { account = "1200", side = "debit", amount = "120.00" },

examples/projects-invoice-and-bill-lines-count-by-project.toml

@@ -95,6 +95,7 @@ bill = { vendor = "Dana Illustration", lines = [
 [[events]]
 date = "2026-03-20"
 description = "Cedar pays invoice 1"
+older = true
 lines = [
   { account = "1000", side = "debit", amount = "3800.00" },
   { account = "1200", side = "credit", amount = "3800.00" },
@@ -103,6 +104,7 @@ lines = [
 [[events]]
 date = "2026-03-30"
 description = "Pay Dana's bill"
+older = true
 payee = "Dana Illustration"
 lines = [
   { account = "2000", side = "debit", amount = "1250.00" },

examples/projects-net-is-its-tagged-lines.toml

@@ -33,7 +33,7 @@ code = "1000"
 name = "Cash"
 type = "asset"
 [[setup.accounts]]
-code = "1200"
+code = "1500"
 name = "Equipment"
 type = "asset"
 [[setup.accounts]]
@@ -93,7 +93,7 @@ lines = [
 date = "2026-03-05"
 description = "Test devices for Beta"
 lines = [
-  { account = "1200", side = "debit", amount = "900.00", project = "Beta" },
+  { account = "1500", side = "debit", amount = "900.00", project = "Beta" },
   { account = "1000", side = "credit", amount = "900.00" },
 ]
 [[events]]