feat: revenue_concept = c("general", "total") off the crosswalk (#12)

Closes the last blocked test in the suite. Owner ruled both halves of the
open question yes on 2026-07-30.

`cog_revenue()` gains `revenue_concept`, mirroring `expenditure_concept`,
with Census's two published concepts defined as crosswalk
`revenue_subtype` sets rather than item-code prefixes:

  general = own_source + federal + state + local_aid   (the default)
  total   = general + utility + liquor_store + insurance_trust

The manual defines the first by subtracting the other three from the
second (4.3), so both are computable only once all four families are
named -- which cog_pipeline#79 does. Insurance trust now includes the
employee-retirement X codes (X01/X02/X05/X08) alongside the Y codes.

- inst/sql: revenue_long / revenue_long_harmonized carry EVERY revenue
  subtype; the concept narrows in R via the existing subtype_scope
  machinery, exactly as expenditure_concept narrows spending_long.
- cog_explain() now prints each verb's OWN concept. It previously
  printed `expenditure_concept` unconditionally, so a cog_revenue()
  caller was told "Concept: primary" -- a spending concept their result
  has nothing to do with.
- Fixture regenerated at pipeline_commit aadb46b (330 crosswalk rows).

Corrected two stale expectations in the blocked test while un-skipping
it. It asserted X01+X04+X05+X08 and omitted X02, which applies to state
governments and is nonzero for Wisconsin; X04 is an exhibit code for an
INTRAgovernmental transfer that Census's own "Total Emp Ret Rev"
excludes. Verified against that Census field: the right set is
X01+X02+X05+X08 = $2,283,883k, exactly. And its expected `total` of
$33,377,093k predated the Y codes being classified -- complete Total
Revenue for WI FY2012 is $34,881,961k (general 31,338,293 + Y 1,259,785
+ X 2,283,883).

Behaviour change worth knowing: `general` is now STRICT Census General
Revenue, so utility and liquor store revenue leave the default. Measured
on the fixture that is 15.9% of what cog_revenue() returned for cities,
vs 1.2% for states and 1.7% for counties.

Suite: 716 pass / 0 fail / 0 skip -- the first time this package has had
no skipped tests.

Closes #12

inst/extdata/fixture_corpus/manifest.json

@@ -1,7 +1,7 @@
 {
   "schema_version": 6,
-  "built_at": "2026-07-30T20:01:56Z",
-  "pipeline_commit": "e64a046",
+  "built_at": "2026-07-31T00:47:27Z",
+  "pipeline_commit": "aadb46b",
   "fixture_note": "Four-year (2011, 2012, 2019, 2020) fixture for uscogdata tests. Full corpus available via USCOGDATA_URL. Regenerated from the sparsified schema-v6 corpus: the wide era (<= FY2011) no longer stores explicit zeros, so FY2011 absence means Census published $0 while FY2012+ absence means not reported. representation.parquet and code_set.parquet carry that rule and ship in full, as do every other metadata table in the publish tree. 2011/2012 straddle both the wide-aggregate -> modern-leaf format boundary (exercised by basis=\"harmonized\" and recipe= queries) and the dense -> sparse representation boundary (SB194); 2019/2020 retain the prior per-capita/CPI regression anchors. Regenerated via data-raw/regenerate_fixture_corpus.R.",
   "data_vintage": {
     "source_vintages": {
@@ -105,12 +105,12 @@
       },
       {
         "path": "data/series_breaks.parquet",
-        "sha256": "381090660c8b8a1bee852e7f63d29b9ecaf10f71870f41c63de92017c83b6f1f",
+        "sha256": "06dcc995ff533e57cc65fa25086cc9bf83ba592c58bf7cc99269dc2576f69944",
         "description": "series_breaks.parquet"
       },
       {
         "path": "data/summary_categories.parquet",
-        "sha256": "e4918abf8e9e6d1372d7ddc255dc199f9c303e250f4106449241b48c68abee67",
+        "sha256": "e3b0efa00ce713b8f45829b89cfde24b55333f26101f0495df82d85997d18d8e",
         "description": "summary_categories.parquet"
       }
     ]