feat: package skeleton — DESCRIPTION, NAMESPACE, session/manifest/cache/views

Minimal skeleton for uscogdata v0.1. Internal session layer with lazy
cog_open(), manifest fetch+validate+cache, view registration placeholder.
Depends on DuckDB >=1.0, httr2, jsonlite. inst/schemas/provenance-v1.json
ships the structured provenance JSON Schema.

R/views.R

@@ -0,0 +1,13 @@
+# R/views.R
+
+#' Register DuckDB views from inst/sql/ SQL files
+#' @noRd
+.register_views <- function(con, url, manifest) {
+  sql_dir <- system.file("sql", package = "uscogdata")
+  files   <- list.files(sql_dir, pattern = "\\.sql$", full.names = TRUE)
+  for (f in files) {
+    sql <- paste(readLines(f, warn = FALSE), collapse = "\n")
+    sql <- gsub("\\{url\\}", url, sql, fixed = FALSE)
+    DBI::dbExecute(con, sql)
+  }
+}