Parties, attachment links, statements, reconciliations (store), TIN vault crate

Parties: one directory for vendors, contractors, customers, employees,
members, platforms, agencies, banks, landlords (ledger-core parties.rs).
W-9/W-4 facts without the number (last four only; any nine-digit run in a
party field is refused, Treas. Reg. 301.6109-4). Vendor and customer
records link to parties on replay; core tags every bill, invoice, payment,
and reversal with its counterparty. Journal events party.*,
entry.party_set; payroll lines name the employee party.

MCP: books.add_party, update_party, set_party_roles, set_w9, set_w4,
parties, party, set_entry_party; draft_entry party; run_payroll employee;
show party. Viewer: Parties directory and party pages, search, journal
text, W-9 attention, demo data.

One definition of a party's money (ledger_core::parties::activity) for
MCP and viewer. 1099 amounts count payments from cash and financing
accounts (a member paying for the company counts; a card doesn't; a
prepayment counts when made): vendor_1099_report_with, B-19.

Store: attachment links to any subject, statements, reconciliations
(schema v11), with replay and projection. ledger-vault: encrypted TIN and
W-9 records (ChaCha20-Poly1305, key file outside the books).

Spec-blind tests for parties (core, store, MCP, viewer) and attachments.

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

crates/ledger-gui/src/app.rs

@@ -22,6 +22,7 @@ pub struct PageState {
     pub reports: pages::reports::State,
     pub accounts: pages::accounts::State,
     pub assets: pages::assets::State,
+    pub parties: pages::parties::State,
     pub documents: pages::documents::State,
     pub journal: pages::journal::State,
 }
@@ -123,6 +124,7 @@ impl App {
                 "reports" => Route::Reports(ReportKind::ProfitAndLoss),
                 "accounts" => Route::Accounts,
                 "assets" => Route::Assets,
+                "parties" => Route::Parties,
                 "documents" => Route::Documents,
                 "company" => Route::Company,
                 "journal" => Route::Journal,
@@ -191,6 +193,12 @@ impl App {
                 }
                 Route::Asset(asset_id)
             }
+            T::Party { party_id } => {
+                if b.ledger.get_party(party_id).is_none() {
+                    return;
+                }
+                Route::Party(party_id)
+            }
             T::Search { query } => {
                 let st = &mut self.state.transactions;
                 st.query = query;