fix(s3/lifecycle): WalkerDispatcher uses entry.Path for ABORT_MPU + shell announces load

Two CI-surfaced bugs caught by PR #9471's S3 Lifecycle Tests run on
master after PRs #9475 + #9466:

1. Walker dispatch for ABORT_MPU was sending entry.DestKey as
   req.ObjectPath. The server's ABORT_MPU handler
   (weed/s3api/s3api_internal_lifecycle.go) strips the .uploads/
   prefix to extract the upload id and reads the init record from
   that directory, so it expects the .uploads/<id> path verbatim.
   DestKey looks like a regular object path; the server's prefix
   check fails and the dispatch returns BLOCKED with
   "FATAL_EVENT_ERROR: ABORT_MPU object_path missing .uploads/
   prefix". The test fix renames TestWalkerDispatcher_MPUInitUsesDestKey
   to ...UsesUploadsPath and inverts the assertion to match the
   actual server contract.

   DestKey is still used for the WalkBuckets shard predicate and
   for rule-prefix matching in bootstrap.walker; both surfaces want
   the user's intended path, while DISPATCH wants the .uploads/<id>
   directory. The bootstrap test
   (TestLifecycleAbortIncompleteMultipartUpload) caught this when
   the walker's BLOCKED error surfaced as FATAL output.

2. test/s3/lifecycle/s3_lifecycle_empty_bucket_test.go asserts the
   shell command logs "loaded lifecycle for N bucket(s)" so a
   regression that produces half-shaped output (no load summary)
   is caught. The restored shell command (PR #9475) didn't print
   that line; add it back on the first pass that finds non-zero
   inputs.

weed/s3api/s3lifecycle/dailyrun/walker_dispatcher.go

@@ -35,16 +35,18 @@ func (d *WalkerDispatcher) Delete(ctx context.Context, action *engine.CompiledAc
 	}
 	objectPath := entry.Path
 	if entry.IsMPUInit {
-		// Rule-prefix matching used DestKey; the server takes the
-		// canonical object path for the LifecycleDelete RPC, which
-		// is also DestKey. The walker hits the .uploads/<id>
-		// directory itself only when ActionKind=ABORT_MPU, and the
-		// server resolves the upload from (bucket, object_path) +
-		// the init record's metadata.
+		// Rule-prefix matching uses DestKey (the user's intended
+		// object key); dispatch uses entry.Path (.uploads/<id>),
+		// which is what the server's ABORT_MPU handler expects in
+		// req.ObjectPath — it strips the .uploads/ prefix to get
+		// the upload id and reads the init record from that
+		// directory. DestKey is the dispatch ANTI-pattern here: it
+		// looks like a regular object path, the server's check for
+		// the .uploads/ prefix fails, and the dispatch comes back
+		// as BLOCKED FATAL_EVENT_ERROR.
 		if entry.DestKey == "" {
 			return fmt.Errorf("walker dispatch: MPU init entry with empty DestKey: %s", entry.Path)
 		}
-		objectPath = entry.DestKey
 	}
 	rh := action.Key.RuleHash
 	req := &s3_lifecycle_pb.LifecycleDeleteRequest{

weed/s3api/s3lifecycle/dailyrun/walker_dispatcher_test.go

@@ -72,9 +72,11 @@ func TestWalkerDispatcher_VersionedPassesVersionID(t *testing.T) {
 	assert.Equal(t, "v-abc", c.lastReq.VersionId)
 }
 
-func TestWalkerDispatcher_MPUInitUsesDestKey(t *testing.T) {
-	// Rule-prefix matching used DestKey; the RPC ObjectPath must match
-	// so the server resolves the upload from the user's intended key.
+func TestWalkerDispatcher_MPUInitUsesUploadsPath(t *testing.T) {
+	// Rule-prefix matching uses DestKey to decide IF this MPU init
+	// matches; dispatch uses Path (.uploads/<id>) because the server's
+	// ABORT_MPU handler strips the .uploads/ prefix to get the upload
+	// id. Sending DestKey here would BLOCK with FATAL_EVENT_ERROR.
 	c := &walkerStubClient{outcome: s3_lifecycle_pb.LifecycleDeleteOutcome_DONE}
 	d := &WalkerDispatcher{Client: c}
 	a := sampleAction(t, s3lifecycle.ActionKindAbortMPU)
@@ -84,7 +86,7 @@ func TestWalkerDispatcher_MPUInitUsesDestKey(t *testing.T) {
 		IsMPUInit: true,
 	})
 	require.NoError(t, err)
-	assert.Equal(t, "user/path/object", c.lastReq.ObjectPath)
+	assert.Equal(t, ".uploads/abc123", c.lastReq.ObjectPath)
 }
 
 func TestWalkerDispatcher_MPUInitEmptyDestKeyErrors(t *testing.T) {

weed/shell/command_s3_lifecycle_run_shard.go

@@ -122,6 +122,7 @@ func (c *commandS3LifecycleRunShard) Do(args []string, env *CommandEnv, writer i
 		fmt.Fprintf(writer, "running shards %s (event budget=%d, runtime=%s, refresh=%s)…\n",
 			formatShardLabel(shards), *eventBudget, *runtime, *cadence)
 
+		announcedLoad := false
 		runPass := func() error {
 			eng := engine.New()
 			inputs, parseErrors, err := scheduler.LoadCompileInputs(ctx, filerClient, bucketsPath)
@@ -140,6 +141,10 @@ func (c *commandS3LifecycleRunShard) Do(args []string, env *CommandEnv, writer i
 			if len(inputs) == 0 {
 				return nil
 			}
+			if !announcedLoad {
+				fmt.Fprintf(writer, "loaded lifecycle for %d bucket(s)\n", len(inputs))
+				announcedLoad = true
+			}
 			buckets := make([]string, 0, len(inputs))
 			for _, in := range inputs {
 				if in.Bucket != "" {