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-store/src/viewer.rs

@@ -16,7 +16,7 @@ use std::path::{Path, PathBuf};
 #[serde(tag = "show", rename_all = "snake_case")]
 pub enum ViewerTarget {
     /// A top-level page: overview, cash, profit, transactions, reports,
-    /// accounts, assets, documents, company, journal.
+    /// accounts, assets, parties, documents, company, journal.
     Page {
         /// Page name.
         page: String,
@@ -62,6 +62,12 @@ pub enum ViewerTarget {
         /// Asset id.
         asset_id: u64,
     },
+    /// One party: who they are, their roles, and everything the company
+    /// did with them.
+    Party {
+        /// Party id.
+        party_id: u64,
+    },
     /// The transactions list, searched.
     Search {
         /// Search text: description, account, vendor, amount.