chore: remove ~50k lines of unreachable dead code (#8913)

* chore: remove unreachable dead code across the codebase

Remove ~50,000 lines of unreachable code identified by static analysis.

Major removals:
- weed/filer/redis_lua: entire unused Redis Lua filer store implementation
- weed/wdclient/net2, resource_pool: unused connection/resource pool packages
- weed/plugin/worker/lifecycle: unused lifecycle plugin worker
- weed/s3api: unused S3 policy templates, presigned URL IAM, streaming copy,
  multipart IAM, key rotation, and various SSE helper functions
- weed/mq/kafka: unused partition mapping, compression, schema, and protocol functions
- weed/mq/offset: unused SQL storage and migration code
- weed/worker: unused registry, task, and monitoring functions
- weed/query: unused SQL engine, parquet scanner, and type functions
- weed/shell: unused EC proportional rebalance functions
- weed/storage/erasure_coding/distribution: unused distribution analysis functions
- Individual unreachable functions removed from 150+ files across admin,
  credential, filer, iam, kms, mount, mq, operation, pb, s3api, server,
  shell, storage, topology, and util packages

* fix(s3): reset shared memory store in IAM test to prevent flaky failure

TestLoadIAMManagerFromConfig_EmptyConfigWithFallbackKey was flaky because
the MemoryStore credential backend is a singleton registered via init().
Earlier tests that create anonymous identities pollute the shared store,
causing LookupAnonymous() to unexpectedly return true.

Fix by calling Reset() on the memory store before the test runs.

* style: run gofmt on changed files

* fix: restore KMS functions used by integration tests

* fix(plugin): prevent panic on send to closed worker session channel

The Plugin.sendToWorker method could panic with "send on closed channel"
when a worker disconnected while a message was being sent. The race was
between streamSession.close() closing the outgoing channel and sendToWorker
writing to it concurrently.

Add a done channel to streamSession that is closed before the outgoing
channel, and check it in sendToWorker's select to safely detect closed
sessions without panicking.

weed/pb/filer_pb/filer_client.go

@@ -93,11 +93,6 @@ func List(ctx context.Context, filerClient FilerClient, parentDirectoryPath, pre
 	})
 }
 
-func doList(ctx context.Context, filerClient FilerClient, fullDirPath util.FullPath, prefix string, fn EachEntryFunction, startFrom string, inclusive bool, limit uint32) (err error) {
-	_, err = doListWithSnapshot(ctx, filerClient, fullDirPath, prefix, fn, startFrom, inclusive, limit, 0)
-	return err
-}
-
 func doListWithSnapshot(ctx context.Context, filerClient FilerClient, fullDirPath util.FullPath, prefix string, fn EachEntryFunction, startFrom string, inclusive bool, limit uint32, snapshotTsNs int64) (actualSnapshotTsNs int64, err error) {
 	err = filerClient.WithFilerClient(false, func(client SeaweedFilerClient) error {
 		actualSnapshotTsNs, err = DoSeaweedListWithSnapshot(ctx, client, fullDirPath, prefix, fn, startFrom, inclusive, limit, snapshotTsNs)
@@ -212,26 +207,6 @@ func Exists(ctx context.Context, filerClient FilerClient, parentDirectoryPath st
 	return
 }
 
-func Touch(ctx context.Context, filerClient FilerClient, parentDirectoryPath string, entryName string, entry *Entry) (err error) {
-
-	return filerClient.WithFilerClient(false, func(client SeaweedFilerClient) error {
-
-		request := &UpdateEntryRequest{
-			Directory: parentDirectoryPath,
-			Entry:     entry,
-		}
-
-		glog.V(4).InfofCtx(ctx, "touch entry %v/%v: %v", parentDirectoryPath, entryName, request)
-		if err := UpdateEntry(ctx, client, request); err != nil {
-			glog.V(0).InfofCtx(ctx, "touch exists entry %v: %v", request, err)
-			return fmt.Errorf("touch exists entry %s/%s: %v", parentDirectoryPath, entryName, err)
-		}
-
-		return nil
-	})
-
-}
-
 func Mkdir(ctx context.Context, filerClient FilerClient, parentDirectoryPath string, dirName string, fn func(entry *Entry)) error {
 	return filerClient.WithFilerClient(false, func(client SeaweedFilerClient) error {
 		return DoMkdir(ctx, client, parentDirectoryPath, dirName, fn)
@@ -349,59 +324,3 @@ func DoRemoveWithResponse(ctx context.Context, client SeaweedFilerClient, parent
 		return resp, nil
 	}
 }
-
-// DoDeleteEmptyParentDirectories recursively deletes empty parent directories.
-// It stops at root "/" or at stopAtPath.
-// For safety, dirPath must be under stopAtPath (when stopAtPath is provided).
-// The checked map tracks already-processed directories to avoid redundant work in batch operations.
-func DoDeleteEmptyParentDirectories(ctx context.Context, client SeaweedFilerClient, dirPath util.FullPath, stopAtPath util.FullPath, checked map[string]bool) {
-	if dirPath == "/" || dirPath == stopAtPath {
-		return
-	}
-
-	// Skip if already checked (for batch delete optimization)
-	dirPathStr := string(dirPath)
-	if checked != nil {
-		if checked[dirPathStr] {
-			return
-		}
-		checked[dirPathStr] = true
-	}
-
-	// Safety check: if stopAtPath is provided, dirPath must be under it (root "/" allows everything)
-	stopStr := string(stopAtPath)
-	if stopAtPath != "" && stopStr != "/" && !strings.HasPrefix(dirPathStr+"/", stopStr+"/") {
-		glog.V(1).InfofCtx(ctx, "DoDeleteEmptyParentDirectories: %s is not under %s, skipping", dirPath, stopAtPath)
-		return
-	}
-
-	// Check if directory is empty by listing with limit 1
-	isEmpty := true
-	err := SeaweedList(ctx, client, dirPathStr, "", func(entry *Entry, isLast bool) error {
-		isEmpty = false
-		return io.EOF // Use sentinel error to explicitly stop iteration
-	}, "", false, 1)
-
-	if err != nil && err != io.EOF {
-		glog.V(3).InfofCtx(ctx, "DoDeleteEmptyParentDirectories: error checking %s: %v", dirPath, err)
-		return
-	}
-
-	if !isEmpty {
-		// Directory is not empty, stop checking upward
-		glog.V(3).InfofCtx(ctx, "DoDeleteEmptyParentDirectories: directory %s is not empty, stopping cleanup", dirPath)
-		return
-	}
-
-	// Directory is empty, try to delete it
-	glog.V(2).InfofCtx(ctx, "DoDeleteEmptyParentDirectories: deleting empty directory %s", dirPath)
-	parentDir, dirName := dirPath.DirAndName()
-
-	if err := DoRemove(ctx, client, parentDir, dirName, false, false, false, false, nil); err == nil {
-		// Successfully deleted, continue checking upwards
-		DoDeleteEmptyParentDirectories(ctx, client, util.FullPath(parentDir), stopAtPath, checked)
-	} else {
-		// Failed to delete, stop cleanup
-		glog.V(3).InfofCtx(ctx, "DoDeleteEmptyParentDirectories: failed to delete %s: %v", dirPath, err)
-	}
-}