Don't Panic in getComposeStatus and skip invalid jobs in fsjobqueue New

This handles corrupt job json files by skipping them. They still exist,
and errors are logged, but the system keeps working.

If one or more of the json files in /var/lib/osbuild-composer/jobs/
becomes corrupt they can stop the osbuild-composer service from
starting, or stop commands like 'composer-cli compose status' from
working because they quit on the first error and miss any job that
aren't broken.

internal/jobqueue/fsjobqueue/fsjobqueue.go

@@ -106,7 +106,8 @@ func New(dir string) (*fsJobQueue, error) {
 		}
 		j, err := q.readJob(jobId)
 		if err != nil {
-			return nil, err
+			// Skip invalid jobs, leaving them in place for later examination
+			continue
 		}
 
 		// If a job is running, and not cancelled, track the token

internal/jobqueue/fsjobqueue/fsjobqueue_test.go

@@ -1,6 +1,8 @@
 package fsjobqueue_test
 
 import (
+	"os"
+	"path"
 	"testing"
 
 	"github.com/osbuild/osbuild-composer/pkg/jobqueue"
@@ -28,3 +30,15 @@ func TestNonExistant(t *testing.T) {
 	require.Error(t, err)
 	require.Nil(t, q)
 }
+
+func TestJobQueueBadJSON(t *testing.T) {
+	dir := t.TempDir()
+
+	// Write a purposfully invalid JSON file into the queue
+	err := os.WriteFile(path.Join(dir, "/4f1cf5f8-525d-46b7-aef4-33c6a919c038.json"), []byte("{invalid json content"), 0600)
+	require.Nil(t, err)
+
+	q, err := fsjobqueue.New(dir)
+	require.Nil(t, err)
+	require.NotNil(t, q)
+}