fix(build): stop per-minor objects masking the per-minor candidate list

Two omissions in the snapshot, both the same shape as the ones already
fixed downstream.

s3_dir_ls(recurse = TRUE) walks the per-minor slots, and basename()
throws the directory away, so 4.5/curl_1.0.tar.gz and curl_1.0.tar.gz
collapse to one name. A package present under any R minor then counts as
built for all of them, and the candidate list prunes exactly the packages
a per-minor pass exists to build. arm64/alpine324 reported '0 remaining'
for both 4.4 and 4.6 while the same run's indexes dropped 2407 and 2436
packages as missing for those minors.

Per-minor objects are excluded here and presence is decided downstream,
where the running R version is known: build-all.R filters on it and
build_binary_package() checks the per-minor path per package. Archive/ is
kept, or every superseded version would look unbuilt.

The error query also matched on name, tag, platform and arch only, so a
failure under the primary minor dropped the package from every other
minor's candidate list. Same omission as local/build-all.R and bincraft's
check_package_error(); this is the third and last consumer of that
table.

local/packages-to-build.R

@@ -116,7 +116,28 @@ s3_pkgs <- s3fs::s3_dir_ls(
   recurse = TRUE
 )
 
-file_names <- basename(s3_pkgs)
+# `recurse = TRUE` walks the per-minor slots as well, and `basename()` throws
+# the directory away - so `4.5/curl_1.0.tar.gz` and `curl_1.0.tar.gz` collapse
+# to one name and a package present under *any* R minor counts as built for
+# *all* of them. The candidate list then prunes exactly the packages a
+# per-minor pass exists to build: arm64/alpine324 reported "0 remaining" for
+# both 4.4 and 4.6 while its indexes were dropping 2400+ packages as missing.
+#
+# Per-minor objects are therefore excluded here. Presence in a specific minor
+# is decided downstream, where the running R version is known: build-all.R
+# filters on it, and `build_binary_package()` checks the per-minor path per
+# package and skips what is already there.
+#
+# Archive/ is kept. Those are versions that were built and then superseded;
+# dropping them would make every archived version look unbuilt.
+per_minor_object <- grepl("/[0-9]+\\.[0-9]+/[^/]+$", s3_pkgs)
+if (any(per_minor_object)) {
+  cat(sprintf(
+    "Excluding %d per-minor object(s) from the presence check; those are decided per pass\n",
+    sum(per_minor_object)
+  ))
+}
+file_names <- basename(s3_pkgs[!per_minor_object])
 
 # An object occupying a key is not proof a binary was built: a package whose
 # build failed has its CRAN source published under exactly that name. Left in
@@ -179,11 +200,22 @@ s3_dt <- data.table(
 
 ### Get all packages with build errors
 
+# Scoped to the R minor this snapshot is computed under. A failure is a fact
+# about one interpreter: without the scope a package that failed under the
+# primary minor is dropped from the candidate list for every other minor too,
+# which is the same omission fixed in local/build-all.R and in bincraft's
+# check_package_error().
+snapshot_r_minor <- paste(
+  R.version$major,
+  strsplit(R.version$minor, ".", fixed = TRUE)[[1L]][1L],
+  sep = "."
+)
 sql_query <- paste0(
   # nolint
   "SELECT error_occurred FROM ",
   "single_builds",
-  " WHERE name = $1 AND tag = $2 AND platform = $3 AND arch = $4"
+  " WHERE name = $1 AND tag = $2 AND platform = $3 AND arch = $4",
+  " AND substring(r_version from '^[0-9]+[.][0-9]+') = $5"
 )
 # Function to query for a single package-version
 query_error <- function(pkg, ver) {
@@ -191,7 +223,7 @@ query_error <- function(pkg, ver) {
     ~ DBI::dbGetQuery(
       con,
       sql_query,
-      params = list(pkg, ver, platform, arch)
+      params = list(pkg, ver, platform, arch, snapshot_r_minor)
     ),
     rate = purrr::rate_backoff(
       pause_base = 1L,