feat: 1099 tracking — vendor forms, payment tags, year-end worksheet

Vendors carry form_1099 (NEC/MISC) and tin_on_file (never the TIN).
Entries carry the vendor they paid; bills, bill payments, and reversals
are tagged automatically. books.vendor_1099 counts cash paid per vendor
per calendar year (card payments excluded) against $600 through 2025 and
$2,000 from 2026, or an override, and flags missing W-9s. Four new tools
(64), two journal events, schema v7. Docs: finished R-FUTURE work is no
longer listed as future.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MtYEaR6M6Ybdhm6X98BWNu

crates/ledger-core/src/arap.rs

@@ -42,6 +42,14 @@ pub struct Vendor {
     pub id: VendorId,
     /// Display name.
     pub name: String,
+    /// The information return this vendor gets, if any (see
+    /// [`crate::form1099`]).
+    #[serde(default)]
+    pub form_1099: Option<crate::form1099::Form1099>,
+    /// A W-9 (taxpayer identification number) is on file. The number
+    /// itself is never stored here.
+    #[serde(default)]
+    pub tin_on_file: bool,
 }
 
 /// Payment status of an invoice or bill.