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/tests/screens.rs

@@ -51,6 +51,19 @@ fn screenshots() {
         .next()
         .map(|a| a.id)
         .unwrap_or(1);
+    // A party with the most to show: W-9 facts first, else any.
+    let party = std::env::var("SHOT_PARTY")
+        .ok()
+        .and_then(|p| p.parse().ok())
+        .or_else(|| {
+            loaded
+                .ledger
+                .parties()
+                .find(|p| p.w9.is_some() && p.vendor.is_some())
+                .or_else(|| loaded.ledger.parties().next())
+                .map(|p| p.id)
+        })
+        .unwrap_or(1);
     drop(loaded);
     let routes: Vec<(&str, Route)> = vec![
         ("overview", Route::Overview),
@@ -82,6 +95,8 @@ fn screenshots() {
         ("account", Route::Account(first_cash)),
         ("assets", Route::Assets),
         ("asset", Route::Asset(first_asset)),
+        ("parties", Route::Parties),
+        ("party", Route::Party(party)),
         ("document", Route::Document(last_doc)),
         ("event", Route::JournalEvent(last_event)),
         ("documents", Route::Documents),