complete bin/cvt-submission.sh

Successfully tested `bin/cvt-submission.sh` on a new entry in a new
year that was generated from a submission entry.number directory via
`sbin/post-collect.sh` from the submit tools.

Changed `bin/cvt-submission.sh` prompts to use "[Y,n]" and to default to yes.

The `bin/cvt-submission.sh` processes and appends YYYY/dir to `.allyear`.

Improved 215 error message and exit code from `bin/subst.entry-navbar.awk`.

Changed `bin/cvt-submission.sh` VERSION from "2.0.3 2025-05-18"
to "2.0.4 2025-05-18".

Changed `bin/output-index-author.sh` VERSION from "2.0.0 2025-03-13"
to "2.0.1 2025-05-18".

Changed `bin/output-index-inventory.sh` VERSION from "2.0.0 2025-03-13"
to "2.0.1 2025-05-18".

Changed `bin/output-index-inventory.sh` VERSION from "2.0.1 2025-05-17"
to "2.0.2 2025-05-18".

Changed `bin/subst.entry-index.sh` VERSION from "2.0.1 2025-05-17"
to "2.0.2 2025-05-18".

Changed `bin/subst.entry-navbar.awk` VERSION from "1.3.1 2025-05-17"
to "1.3.2 2025-05-18".

Update sitemap.

Tested the above via `make update` on macOS.

bin/output-index-author.sh

@@ -122,7 +122,7 @@ export LC_ALL="C"
 
 # set variables referenced in the usage message
 #
-export VERSION="2.0.0 2025-03-13"
+export VERSION="2.0.1 2025-05-18"
 NAME=$(basename "$0")
 export NAME
 export V_FLAG=0
@@ -640,8 +640,8 @@ if [[ ! -d $YEAR_DIR ]]; then
 fi
 export ENTRY_ID="${YEAR_DIR}_${ENTRY_DIR}"
 export DOT_YEAR="$YEAR_DIR/.year"
-if [[ ! -s $DOT_YEAR ]]; then
-    echo "$0: ERROR: not a non-empty file: $DOT_YEAR" 1>&2
+if [[ ! -f $DOT_YEAR ]]; then
+    echo "$0: ERROR: not a file: $DOT_YEAR" 1>&2
     exit 6
 fi
 # Now that we have moved to topdir, form and verify YYYY_DIR is a writable directory