shell: make every -collection flag parse the same way (#11794)

* shell: make every -collection flag parse the same way

The filter vocabulary (comma-separated names, wildcards, regexes,
"_default" for the empty-named collection) already existed in
wildcard.CompileCollectionMatcher, but several commands still did their
own exact-match comparison or sent the raw flag value to servers.

fs.mergeVolumes used a literal string compare, so -collection=_default
silently produced an empty merge plan; it now uses the shared matcher
while keeping "*" as the match-all default. volume.fsck and volume.mark
filter through the matcher too, and volume.vacuum resolves the filter
client-side into per-collection and per-volume requests, since no
Collection value scopes the VacuumVolume RPC to the unnamed collection
alone.

Commands that put one concrete collection name on the wire normalize
"_default" to "" (volume.grow, fs.configure, mq.topic.compact,
collection.delete, ec.rebuild, ec.balance), and the tier -volumeId
commands resolve the volume's actual collection from topology first so
patterns and named-collection requests pass the volume server's
collection check.

* shell: spell the default-collection keyword via CollectionDefault

* shell: address review findings on collection filter handling

volume.fsck keeps a set of every volume the master knows before any
filtering, so a filer entry whose volume was excluded by -collection or
-volumeId is skipped instead of reported "volume not found" and deleted
by -reallyDeleteFilerEntries. The collection filter also no longer
scopes the filer walk to /buckets/<collection>: fs.configure can bind a
collection to any path prefix, and a narrower walk could mark live
chunks as orphans under -reallyDeleteFromVolume.

ec.rebuild and ec.balance resolve -collection through the new
wildcard.ExpandCollectionFilter, which passes literal names through even
when the master does not list them — ec.rebuild must be able to recover
a collection whose shards all lost their index and never registered.

fs.configure and mq.topic.compact now reject _default outright: an empty
Collection means "unset" in both the path-rule merge and the filer's
storage-option fallback chain, so the keyword would have been silently
ignored.

The unnamed-collection vacuum sweep keeps the master's low-disk-space
exception: a volume whose every replica is read-only is probed with
VacuumVolumeCheck and stays eligible when a replica reports
DiskSpaceLow, instead of being dropped outright.

weed/shell/command_ec_rebuild.go

@@ -10,6 +10,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/ec"
 	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
 	"github.com/seaweedfs/seaweedfs/weed/storage/types"
+	"github.com/seaweedfs/seaweedfs/weed/util/wildcard"
 )
 
 func init() {
@@ -73,7 +74,7 @@ func (c *commandEcRebuild) HasTag(CommandTag) bool {
 func (c *commandEcRebuild) Do(args []string, commandEnv *CommandEnv, writer io.Writer) (err error) {
 
 	fixCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
-	collection := fixCommand.String("collection", "EACH_COLLECTION", "collection name, or \"EACH_COLLECTION\" for each collection")
+	collection := fixCommand.String("collection", string(wildcard.CollectionFilterEach), "comma-separated collection names, wildcards, or regex patterns, \""+CollectionDefault+"\" for the collection with no name, or \""+string(wildcard.CollectionFilterEach)+"\" for each collection")
 	volumeIdsStr := fixCommand.String("volumeIds", "", "optional comma-separated list of volume ID to process; defaults to all volumes in the collection")
 	maxParallelization := fixCommand.Int("maxParallelization", DefaultMaxParallelization, "run up to X tasks in parallel, whenever possible")
 	applyChanges := fixCommand.Bool("apply", false, "apply the changes")
@@ -98,14 +99,9 @@ func (c *commandEcRebuild) Do(args []string, commandEnv *CommandEnv, writer io.W
 		return err
 	}
 
-	var collections []string
-	if *collection == "EACH_COLLECTION" {
-		collections, err = ListCollectionNames(commandEnv, false, true)
-		if err != nil {
-			return err
-		}
-	} else {
-		collections = []string{*collection}
+	collections, err := resolveEcCollections(commandEnv, *collection)
+	if err != nil {
+		return err
 	}
 
 	var volumeIds []needle.VolumeId