feat: three-concept expenditure model classified by crosswalk membership (#11)

Rewrites expenditure/revenue classification off item-code first-letter
prefixes and onto summary_categories membership (F-018: prefix Y spans
revenue, expenditure, and balance codes), and exposes
expenditure_concept = c("primary", "direct", "total") with primary as
the new default:

  primary = operations + capital + assistance
  direct  = primary + interest + insurance_benefits   (Census Direct)
  total   = direct + intergovernmental                (M/L/Q via ig views)

- inst/sql: flow views (20-25) select by crosswalk membership;
  summary_categories moves to 11- so it registers before them (DuckDB
  binds view sources eagerly). The IG leg gains Q11/Q12/Q18 state
  school-system payments (F-017).
- R: one subtype scope per verb call drives the verb SQL, the
  harmonization exclusion count, and the complete = TRUE grid;
  flow_prefixes survives only to scope recipe suggestions.
  cog_geographic_rollup/cog_peer_compare accept primary|direct, still
  refuse total, and now actually pass the concept through.
- Balance codes can never reach a spending or revenue result
  (uscogdata#25), asserted at both view and verb level.
- Deletes the #11 skip; per the 2026-07-30 owner ruling the F-018 Y01
  proof is asserted against the crosswalk, not the default
  cog_revenue() call (which stays General Revenue pending #12).

Suite: 696 pass / 0 fail / 1 skip (#12, expected).

Closes #11

tests/testthat/test-expenditure-concept.R

@@ -13,9 +13,13 @@ test_that("the corpus contains no K-prefix rows, so the Direct leg omits K", {
   }
 })
 
-test_that("expenditure_concept defaults to direct and preserves today's numbers", {
+test_that("expenditure_concept defaults to primary; direct matches it on a pure operations/capital category", {
   gov <- "010000226085"                      # Alabama state government
   base <- cog_spending(gov, years = 2019, category = "Police")
+  expect_equal(attr(base, "provenance")$expenditure_concept, "primary")
+  # Police maps only to operations/capital codes (E62/F62/G62), so the
+  # direct concept's extra subtypes (interest, insurance_benefits) cannot
+  # contribute and the two concepts must agree exactly here.
   expl <- cog_spending(gov, years = 2019, category = "Police",
                        expenditure_concept = "direct")
   expect_equal(base$amt_nominal, expl$amt_nominal)
@@ -59,7 +63,9 @@ test_that("the IG leg never includes the L-- family total", {
   codes <- DBI::dbGetQuery(con,
     "SELECT DISTINCT item_code FROM ig_long")$item_code
   expect_false(any(grepl("--$", codes)))
-  expect_true(all(substr(codes, 1, 1) %in% c("M", "L")))
+  # Q joined the IG family with the crosswalk-membership rewrite
+  # (uscogdata#11 / F-017: Q11/Q12/Q18 are state payments to school systems).
+  expect_true(all(substr(codes, 1, 1) %in% c("M", "L", "Q")))
 })
 
 test_that("expenditure_concept rejects unknown values", {
@@ -246,9 +252,12 @@ test_that("both cross-government verbs still accept the direct default", {
 })
 
 test_that("provenance always records the expenditure concept", {
-  d <- cog_spending("010000226085", years = 2019, category = "Police")
+  p <- cog_spending("010000226085", years = 2019, category = "Police")
+  d <- cog_spending("010000226085", years = 2019, category = "Police",
+                    expenditure_concept = "direct")
   t <- cog_spending("010000226085", years = 2019, category = "Police",
                     expenditure_concept = "total")
+  expect_equal(attr(p, "provenance")$expenditure_concept, "primary")
   expect_equal(attr(d, "provenance")$expenditure_concept, "direct")
   expect_equal(attr(t, "provenance")$expenditure_concept, "total")
   # The note explains the non-obvious part: how legacy IG was assembled.