fix workflow: gate filter lookup on primaryRef.filter being set

`args.columns.getColumn("filter")` panics with "Column not found"
when the bundle pool doesn't carry the "filter" key. wf.prepare only
addSingle's the filter when the user picked one, so the unconditional
getColumn at body time blew up for every run that didn't pick a
filter (i.e. the default path).

Gate the lookup + sidecar staging on the same
`is_undefined(args.primaryRef.filter)` check we use in prepare so the
two stay in sync.

Author: xnacly

workflow/src/main.tpl.tengo

@@ -118,10 +118,12 @@ wf.body(func(args) {
 	cmd = withSidecar(cmd, "perResidueConfidence", "per_residue_confidence.tsv", "--per-residue-confidence") // R4 fallback
 
 	// R1 PrimaryRef.filter: single column (vs the multi-column lookups
-	// above), so use the corresponding `getColumn` accessor.
-	filterCol := args.columns.getColumn("filter")
-	if !is_undefined(filterCol) {
-		filterTsv := xsv.exportFrame([filterCol], "tsv", { mem: "1GiB", cpu: 1 })
+	// above), so use the `getColumn` accessor. The bundle only carries
+	// "filter" when wf.prepare actually addSingle'd it, so we gate on the
+	// same `primaryRef.filter` undefined check; `getColumn` panics if the
+	// key isn't in the pool.
+	if !is_undefined(args.primaryRef.filter) {
+		filterTsv := xsv.exportFrame([args.columns.getColumn("filter")], "tsv", { mem: "1GiB", cpu: 1 })
 		cmd = cmd.
 			addFile("clonotype_filter.tsv", filterTsv).
 			arg("--clonotype-filter").arg("clonotype_filter.tsv")