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/worker/worker.go

@@ -383,31 +383,6 @@ func (w *Worker) setReqTick(tick *time.Ticker) *time.Ticker {
 	return w.getReqTick()
 }
 
-func (w *Worker) getStartTime() time.Time {
-	respCh := make(chan time.Time, 1)
-	w.cmds <- workerCommand{
-		action: ActionGetStartTime,
-		data:   respCh,
-	}
-	return <-respCh
-}
-func (w *Worker) getCompletedTasks() int {
-	respCh := make(chan int, 1)
-	w.cmds <- workerCommand{
-		action: ActionGetCompletedTasks,
-		data:   respCh,
-	}
-	return <-respCh
-}
-func (w *Worker) getFailedTasks() int {
-	respCh := make(chan int, 1)
-	w.cmds <- workerCommand{
-		action: ActionGetFailedTasks,
-		data:   respCh,
-	}
-	return <-respCh
-}
-
 // getTaskLoggerConfig returns the task logger configuration with worker's log directory
 func (w *Worker) getTaskLoggerConfig() tasks.TaskLoggerConfig {
 	config := tasks.DefaultTaskLoggerConfig()
@@ -543,27 +518,6 @@ func (w *Worker) handleStop(cmd workerCommand) {
 	cmd.resp <- nil
 }
 
-// RegisterTask registers a task factory
-func (w *Worker) RegisterTask(taskType types.TaskType, factory types.TaskFactory) {
-	w.registry.Register(taskType, factory)
-}
-
-// GetCapabilities returns the worker capabilities
-func (w *Worker) GetCapabilities() []types.TaskType {
-	return w.config.Capabilities
-}
-
-// GetStatus returns the current worker status
-func (w *Worker) GetStatus() types.WorkerStatus {
-	respCh := make(statusResponse, 1)
-	w.cmds <- workerCommand{
-		action: ActionGetStatus,
-		data:   respCh,
-		resp:   nil,
-	}
-	return <-respCh
-}
-
 // HandleTask handles a task execution
 func (w *Worker) HandleTask(task *types.TaskInput) error {
 	glog.V(1).Infof("Worker %s received task %s (type: %s, volume: %d)",
@@ -579,26 +533,6 @@ func (w *Worker) HandleTask(task *types.TaskInput) error {
 	return nil
 }
 
-// SetCapabilities sets the worker capabilities
-func (w *Worker) SetCapabilities(capabilities []types.TaskType) {
-	w.config.Capabilities = capabilities
-}
-
-// SetMaxConcurrent sets the maximum concurrent tasks
-func (w *Worker) SetMaxConcurrent(max int) {
-	w.config.MaxConcurrent = max
-}
-
-// SetHeartbeatInterval sets the heartbeat interval
-func (w *Worker) SetHeartbeatInterval(interval time.Duration) {
-	w.config.HeartbeatInterval = interval
-}
-
-// SetTaskRequestInterval sets the task request interval
-func (w *Worker) SetTaskRequestInterval(interval time.Duration) {
-	w.config.TaskRequestInterval = interval
-}
-
 // SetAdminClient sets the admin client
 func (w *Worker) SetAdminClient(client AdminClient) {
 	w.cmds <- workerCommand{
@@ -828,11 +762,6 @@ func (w *Worker) requestTasks() {
 	}
 }
 
-// GetTaskRegistry returns the task registry
-func (w *Worker) GetTaskRegistry() *tasks.TaskRegistry {
-	return w.registry
-}
-
 // connectionMonitorLoop monitors connection status
 func (w *Worker) connectionMonitorLoop() {
 	ticker := time.NewTicker(30 * time.Second) // Check every 30 seconds
@@ -867,34 +796,6 @@ func (w *Worker) connectionMonitorLoop() {
 	}
 }
 
-// GetConfig returns the worker configuration
-func (w *Worker) GetConfig() *types.WorkerConfig {
-	return w.config
-}
-
-// GetPerformanceMetrics returns performance metrics
-func (w *Worker) GetPerformanceMetrics() *types.WorkerPerformance {
-
-	uptime := time.Since(w.getStartTime())
-	var successRate float64
-	totalTasks := w.getCompletedTasks() + w.getFailedTasks()
-	if totalTasks > 0 {
-		successRate = float64(w.getCompletedTasks()) / float64(totalTasks) * 100
-	}
-
-	return &types.WorkerPerformance{
-		TasksCompleted:  w.getCompletedTasks(),
-		TasksFailed:     w.getFailedTasks(),
-		AverageTaskTime: 0, // Would need to track this
-		Uptime:          uptime,
-		SuccessRate:     successRate,
-	}
-}
-
-func (w *Worker) GetAdmin() AdminClient {
-	return w.getAdmin()
-}
-
 // messageProcessingLoop processes incoming admin messages
 func (w *Worker) messageProcessingLoop() {
 	glog.Infof("MESSAGE LOOP STARTED: Worker %s message processing loop started", w.id)