fix(schedulerclient): parse numeric job_status + object-valued pending_reason

Two bugs surfaced by the new scheduler_pend_reasons tool:
1. The apiserver returns job_status as the numeric XCE state bitmask
   (PEND=0x01, RUN=0x02, EXIT=0x04, DONE=0x08), but getJobs read it with
   rowStr (string), which returns "" for a number → every job mapped to URM
   "unknown", so the pending/running status filter matched nothing.
   → JobStatusFromXCEState(int) + rowURMStatus fallback.
2. pending_reason is a JSON object in the row, not a string; rowStr returned
   "" so Extensions["pending_reason"] was empty and the reason never parsed.
   → rowJSON(key) stores the raw JSON value; the MCP pend_reasons parser
   handles the map form.

schedulerclient tests updated (JobStatusFromXCEState table). mcp-server +
schedulerclient test suites pass; live MCP call now returns the bjobs -p style
explanation for a PEND job.

Co-Authored-By: Claude <noreply@anthropic.com>

src/frontend/schedulerclient/httpclient.go

@@ -308,8 +308,7 @@ func (hc *HTTPClient) getJobs(req *resty.Request, url string, filter JobFilter)
 	jobs := make([]*URMJob, 0, len(rows.Rows))
 	for i := range rows.Rows {
 		j := rows.Rows[i]
-		rawStatus := j.rowStr("job_status")
+		urmStatus := rowURMStatus(j)
-		urmStatus := JobStatusFromString(rawStatus)
 
 		// Apply URM status filter in post-processing
 		if len(filter.Statuses) > 0 {
@@ -358,7 +357,7 @@ func (hc *HTTPClient) getJobs(req *resty.Request, url string, filter JobFilter)
 			HumanID:         j.rowStr("job_id_human"),
 			Name:            j.rowStr("job_name"),
 			Status:          urmStatus,
-			RawStatus:       rawStatus,
+			RawStatus:       rawStatusString(j),
 			Queue:           j.rowStr("queue_name"),
 			Nodes:           j.rowInt("num_hosts"),
 			Cores:           numProcessors,
@@ -372,7 +371,7 @@ func (hc *HTTPClient) getJobs(req *resty.Request, url string, filter JobFilter)
 			Extensions: map[string]any{
 				"command":        j.rowStr("command"),
 				"project_name":   j.rowStr("project_name"),
-				"pending_reason": j.rowStr("pending_reason"),
+				"pending_reason": j.rowJSON("pending_reason"),
 				"resreq":         j.rowStr("resreq"),
 				"exit_status_raw": j.rowStr("exit_status"),
 				"num_processors": numProcessors,
@@ -413,6 +412,40 @@ type apiRow struct {
 }
 
 // rowStr extracts a string field. Missing, null, or non-string → "".
+// rowURMStatus reads a job's status, preferring the string form (PEND/RUN/...)
+// and falling back to the numeric XCE state bitmask the apiserver returns in
+// job_status (rowStr can't unmarshal a number into a string).
+func rowURMStatus(r apiRow) JobStatus {
+	if s := r.rowStr("job_status"); s != "" {
+		return JobStatusFromString(s)
+	}
+	return JobStatusFromXCEState(r.rowInt("job_status"))
+}
+
+// rawStatusString returns the backend-native status value (string form when
+// present, else the numeric state), used for URMJob.RawStatus.
+func rawStatusString(r apiRow) string {
+	if s := r.rowStr("job_status"); s != "" {
+		return s
+	}
+	return strconv.Itoa(r.rowInt("job_status"))
+}
+
+// rowJSON extracts a raw JSON field as a generic value (map/string/...).
+// Missing or null → nil. Used for object-valued fields like pending_reason
+// that rowStr can't read (a JSON object does not unmarshal into a string).
+func (r apiRow) rowJSON(key string) any {
+	raw, ok := r.Data[key]
+	if !ok || string(raw) == "null" {
+		return nil
+	}
+	var v any
+	if err := json.Unmarshal(raw, &v); err != nil {
+		return nil
+	}
+	return v
+}
+
 func (r apiRow) rowStr(key string) string {
 	raw, ok := r.Data[key]
 	if !ok || string(raw) == "null" {

src/frontend/schedulerclient/statusmap.go

@@ -27,6 +27,28 @@ func JobStatusFromString(s string) JobStatus {
 	}
 }
 
+// JobStatusFromXCEState maps the raw numeric XCE job-state bitmask the
+// apiserver returns in job_status (JOB_STAT_PEND=0x01, RUN=0x02, EXIT=0x04,
+// DONE=0x08, PSUSP=0x10, USUSP=0x20, SSUSP=0x40 — src/include/xce/types.h) to
+// a URM JobStatus. Composite states (e.g. RUN|DONE during cleanup) resolve to
+// the most significant, non-PEND state; otherwise fall back to unknown.
+func JobStatusFromXCEState(state int) JobStatus {
+	switch state & 0x7F {
+	case 0x02, 0x0A: // RUN, RUN|DONE
+		return JobStatusRunning
+	case 0x04, 0x0C: // EXIT, EXIT|DONE
+		return JobStatusFailed
+	case 0x08: // DONE
+		return JobStatusSucceeded
+	case 0x10, 0x20, 0x40: // PSUSP/USUSP/SSUSP
+		return JobStatusSuspended
+	case 0x01: // PEND
+		return JobStatusPending
+	default:
+		return JobStatusUnknown
+	}
+}
+
 // ── QueueStatus mapping ─────────────────────────────────────────────────────
 
 // QueueStatusFromString maps the apiserver's composite queue status string

src/frontend/schedulerclient/statusmap_test.go

@@ -1,6 +1,9 @@
 package schedulerclient
 
-import "testing"
+import (
+	"fmt"
+	"testing"
+)
 
 // ── JobStatus mapping tests ─────────────────────────────────────────────────
 
@@ -39,6 +42,32 @@ func TestJobStatusFromString(t *testing.T) {
 	}
 }
 
+func TestJobStatusFromXCEState(t *testing.T) {
+	tests := []struct {
+		input int
+		want  JobStatus
+	}{
+		{0x01, JobStatusPending},   // JOB_STAT_PEND
+		{0x02, JobStatusRunning},   // JOB_STAT_RUN
+		{0x0A, JobStatusRunning},   // RUN|DONE during cleanup
+		{0x04, JobStatusFailed},    // JOB_STAT_EXIT
+		{0x08, JobStatusSucceeded}, // JOB_STAT_DONE
+		{0x10, JobStatusSuspended}, // JOB_STAT_PSUSP
+		{0x20, JobStatusSuspended}, // JOB_STAT_USUSP
+		{0x40, JobStatusSuspended}, // JOB_STAT_SSUSP
+		{0x00, JobStatusUnknown},
+		{0x80, JobStatusUnknown}, // out of the 7-bit state mask
+	}
+	for _, tt := range tests {
+		t.Run(fmt.Sprintf("0x%02x", tt.input), func(t *testing.T) {
+			got := JobStatusFromXCEState(tt.input)
+			if got != tt.want {
+				t.Errorf("JobStatusFromXCEState(0x%02x) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
 // ── QueueStatus mapping tests ────────────────────────────────────────────────
 
 func TestQueueStatusFromString(t *testing.T) {