P3: dated 1099 decisions, payment methods and the card exception (defects 23, 12, 18, D-40)

A vendor's 1099 decision is its own dated fact (files NEC or MISC, not
reportable with its reason, or undetermined), applied by each payment's
date. Payment methods are recorded; card and network payments are left
out and listed; a member's check through financing counts; a bank payment
with no method counts (D-40); $2,000 for payments after 2025. One
worksheet for the tool, the viewer and the CPA package.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

verify/lean/Wanderbooks/Ledger.lean

@@ -131,8 +131,10 @@ inductive Step : Ledger → Ledger → Prop
       Step L { L with posted := L.posted ++ closingFor L p ts id, periods := closeIn p L.periods }
   /-- `apply_settings`, `apply_convention`, `apply_decision`,
   `apply_open_item`, `apply_approval` and their retirements and
-  resolutions: a record of how the books are kept, and nothing else.
-  `rename_account` too: a name is outside the chart the model keeps. -/
+  resolutions, and the 1099 records `set_vendor_1099`,
+  `set_vendor_w9_flag`, `add_instrument` and `set_entry_instrument`: a
+  record of how the books are kept, and nothing else. `rename_account`
+  too: a name is outside the chart the model keeps. -/
   | record (L : Ledger) (r : Nat) : Step L { L with records := r :: L.records }
 
 /-- States reachable from empty books. -/