Audit fixes: party money, reconciliations, require policy, K-1 property

An independent recompute of the real books found no numeric
disagreements; review found 15 defects, all fixed with spec-first
regression tests:

- k1: a prepaid credited straight to capital is property; a member
  paying a vendor through 2100 is cash. Docs and B-13 match.
- parties: a reversal of a reversal counts on its root's side;
  liability-to-liability payments (member pays the card) count as paid.
- viewer: party money uses the server's cash accounts and full calendar
  year; per-party "What for" scales multi-party entries.
- reconciliations: refuse a withdrawn statement before journaling; new
  books.void_statement; reconciled lines can't be un-cleared; one shared
  reconcilable-accounts rule for digest and viewer.
- CPA package includes receipts linked to entries; a file can't be both
  filed on and linked to one entry.
- parties = "require" covers payroll, tax remittance (agency) and
  disposal (buyer); no-party marks follow reversal chains and clear when
  a vendor is tagged.
- derived member shares are frozen to exact amounts when posted, so a
  settings change never re-splits history.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX

crates/ledger-gui/src/pages/journal.rs

@@ -282,6 +282,16 @@ pub fn describe(b: &Books, line: &JournalLine) -> Option<Event> {
                 also: account.map(Route::Account),
             })
         }
+        "statement.voided" => Some(Event {
+            icon: icon::PROHIBIT,
+            text: format!(
+                "Voided the statement recorded on {}: {}",
+                attachment_name(b, att),
+                s(p, "reason")
+            ),
+            route: Some(Route::Document(att)),
+            also: None,
+        }),
         "reconciliation.completed" => {
             let account = p.get("account_id").and_then(|v| v.as_u64());
             let balance = s(p, "statement_balance")