feat(iif): carry each line's project in CLASS, the classes declared first

The P3 cutover review's open point 1: entries carry projects (classes,
B-37), but the QuickBooks Desktop file (B-34) left the CLASS field empty
on every line, and neither B-34 nor the README said so, though B-34 rule
6 says nothing changes silently.

Intuit's IIF Import Kit (vendored in docs/spec/sources/intuit-iif.md,
the kit's SHA-256 unchanged): the `!CLASS` header help says "Only the
NAME column is required" and a subclass's NAME is its parents' names
first, joined by colons; the kit's "Import First - List Declarations"
example declares `!CLASS` rows before any transaction, and its "2004
Deposit (Income)" example names the class line by line in CLASS. So the
file now declares every class in a `!CLASS` list after the accounts and
before `!TRNS`, and writes each line's class in CLASS (empty where the
line has none). Books with no class write no list, byte for byte as
before. A line whose class wasn't declared is refused
(IifError::UndeclaredClass), never written classless.

A class's NAME follows B-34's rules for an account's own name: plain
ASCII (rule 3), a colon written '-' (it would start a subclass),
trimmed, '?' if nothing is left, cut to 31 characters: Intuit's qbXML
Onscreen Reference gives `ClassAdd`'s Name "maxDT" : 31 (and 31 in the
Canadian, UK and Australian desktop editions; 100 only in Online), the
same as its `AccountAdd` Name (both JSON files vendored by SHA-256);
Conductor's QuickBooks Desktop API reference agrees and says the name is
case-insensitive. Classes whose NAMEs would match ignoring case get
" (id)", round after round, as accounts get " (code)", except that
among names that match, those already written differently from the
books (made safe, or tagged) yield first, a second " (id)" if need be:
a class's own name is kept unless another class's own name is the same
ignoring case (classes 1 "Café", 2 "Cafe", 3 "Cafe (1)" are written
"Cafe (1) (1)", "Cafe", "Cafe (1)"). Each class is tagged twice at most
and ids differ, so none is left alike (a hand-built list is refused). Each class name
written differently is an IifChange (IifField::ClassName), said one
line each in the warnings and in the package README, whose
"written differently" paragraph now names class names' limits; its IIF
line says CLASS is each line's project when there are classes. The MCP
and viewer notes count "account or class name(s)".

API: `iif_classes(ledger)` builds the list; `journal_to_iif` takes it
(`&[]` for none).

Docs: rules.md B-34 rule 8 with its sources; intuit-iif.md (the
`!CLASS` help, the list declarations and deposit examples, Intuit's SDK
department page, the qbXML Onscreen Reference's ClassAdd and AccountAdd
and Conductor's class reference, each with SHA-256);
mcp-interface.md (books.export iif, the package note); the bookspec
example iif-quickbooks-journal-file.toml (two projects: one carried and
renamed, one only declared; every line derived by hand); testing.md;
STATUS (open point 1 done; point 3 waits for the close, the owner said).

Tests: ledger-import
`iif_writes_each_lines_class_and_declares_the_classes_first`,
`iif_class_names_fit_quickbooks_and_every_change_is_listed`,
`iif_class_names_written_as_the_books_have_them_are_kept`,
`iif_refuses_an_undeclared_or_unfit_class`, property
`iif_class_names_never_clash`; ledger-package
`the_package_iif_carries_each_lines_project` and the bookspec example.
Broken to confirm: CLASS written empty fails the two exact-file tests,
the package test and the bookspec example; the " (id)" tag dropped fails
the names test and the property; tagging every name that meets (no
yielding) fails the kept-names test and the property (its shrunk case,
"A-B" beside "A\uFF1AB", kept in the regressions file).

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

plan/STATUS.md

@@ -188,11 +188,23 @@ its invoices. The handbook's caveat is gone for books with the feature.
   `projects` but not it, so until the owner's next format upgrade
   (`wanderbooks books upgrade`, D-39) their invoices and bills still take
   none (the handbook says so).
-- Raised by the cutover review (private change log, "Open points"): the
-  IIF leaves its CLASS field empty although entries carry projects; a
+- Raised by the cutover review (private change log, "Open points"): a
   state filing fee is classed as cash paid to suppliers where ASC
   230-10-45-17(c) suggests other operating payments; ties in the per-entry
-  member split all go to the first member.
+  member split all go to the first member (the owner, 2026-10-22: nothing
+  is posted until the year-end close, three weeks off, so it waits).
+  Its first point is done (2026-10-22, B-34 rule 8): the IIF writes each
+  line's project in CLASS, the projects declared first in a `!CLASS`
+  list, their names held to QuickBooks' 31 characters, no two alike, and
+  listed in the README when written differently (tests
+  `iif_writes_each_lines_class_and_declares_the_classes_first`,
+  `iif_class_names_fit_quickbooks_and_every_change_is_listed`,
+  `iif_class_names_written_as_the_books_have_them_are_kept`,
+  `iif_refuses_an_undeclared_or_unfit_class`, the property
+  `iif_class_names_never_clash`, `the_package_iif_carries_each_lines_project`;
+  bookspec `iif-quickbooks-journal-file`). The first company's
+  package changes at its next build: its project-tagged lines carry
+  the class, and the class list is new.
 - The viewer recomputes a long-life asset's whole schedule every frame
   (`ledger-gui` `pages/assets.rs` `schedule`, called from the asset
   page's draw; defect 22's note: slow, never wrong).