feat: basis= harmonized/raw with v4/v5 dual-accept

Adds schema_version 5 support alongside the existing v4 corpus:
.validate_schema() now accepts a supported set (4, 5) instead of a single
expected version, and cog_spending()/cog_revenue() gain basis =
c("harmonized", "raw"). Harmonized basis routes to new
spending_annotated_harmonized / revenue_annotated_harmonized views built on
spending_long_harmonized / revenue_long_harmonized (REPLACE(harmonized_code
AS item_code), excluding aggregate and NA-harmonized rows); raw basis is
byte-identical to the pre-Phase-R2 behavior. On a v4 corpus, an unspecified
basis silently resolves to "raw" with a provenance note; an explicit
basis = "harmonized" aborts with an actionable message.

Provenance gains basis, basis_note, and a harmonization block
(applied/na_rows_excluded/na_amount_excluded). The five new schema-v5-only
SQL views (harmonized long/annotated views, harmonization_map,
harmonization_recipes, series_breaks_pq) are registered conditionally on
manifest$schema_version >= 5, since DuckDB's read_parquet() errors eagerly
at CREATE VIEW time when the backing file doesn't exist on a v4 corpus.

Fixture corpus regenerated to schema_version 5 / years 2011, 2012, 2019,
2020 (2011->2012 spans the wide-aggregate -> modern-leaf format boundary
needed for the harmonization/recipe work), with the harmonization_map /
harmonization_recipes / series_breaks parquet tables bundled alongside the
existing metadata registries.

tests/testthat/test-revenue.R

@@ -36,3 +36,20 @@ test_that("cog_revenue result has provenance attribute", {
 test_that("cog_revenue rejects invalid inputs", {
   expect_error(cog_revenue(list(), 2020L), "character|data frame")
 })
+
+test_that("cog_revenue basis = 'harmonized' (default) matches 'raw' in this fixture window", {
+  skip_if_no_corpus()
+  r_raw  <- cog_revenue("121011212191", 2019:2020, basis = "raw")
+  r_harm <- cog_revenue("121011212191", 2019:2020, basis = "harmonized")
+  expect_equal(attr(r_raw, "provenance")$basis, "raw")
+  expect_equal(attr(r_harm, "provenance")$basis, "harmonized")
+  expect_equal(sum(r_raw$amt_nominal), sum(r_harm$amt_nominal))
+})
+
+test_that("cog_revenue provenance carries the harmonization block", {
+  skip_if_no_corpus()
+  r <- cog_revenue("121011212191", 2020L)
+  h <- attr(r, "provenance")$harmonization
+  expect_true(h$applied)
+  expect_true(h$na_rows_excluded >= 0L)
+})