Admin UI: Fetch task logs (#7114)

* show task details

* loading tasks

* task UI works

* generic rendering

* rendering the export link

* removing placementConflicts from task parameters

* remove TaskSourceLocation

* remove "Server ID" column

* rendering balance task source

* sources and targets

* fix ec task generation

* move info

* render timeline

* simplified worker id

* simplify

* read task logs from worker

* isValidTaskID

* address comments

* Update weed/worker/tasks/balance/execution.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update weed/worker/tasks/erasure_coding/ec_task.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update weed/worker/tasks/task_log_handler.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix shard ids

* plan distributing shard id

* rendering planned shards in task details

* remove Conflicts

* worker logs correctly

* pass in dc and rack

* task logging

* Update weed/admin/maintenance/maintenance_queue.go

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* display log details

* logs have fields now

* sort field keys

* fix link

* fix collection filtering

* avoid hard coded ec shard counts

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

weed/admin/topology/task_management.go

@@ -233,6 +233,8 @@ const (
 type TaskSourceSpec struct {
 	ServerID      string
 	DiskID        uint32
+	DataCenter    string             // Data center of the source server
+	Rack          string             // Rack of the source server
 	CleanupType   SourceCleanupType  // For EC: volume replica vs existing shards
 	StorageImpact *StorageSlotChange // Optional: manual override
 	EstimatedSize *int64             // Optional: manual override
@@ -255,10 +257,3 @@ type TaskSpec struct {
 	Sources      []TaskSourceSpec      // Can be single or multiple
 	Destinations []TaskDestinationSpec // Can be single or multiple
 }
-
-// TaskSourceLocation represents a source location for task creation (DEPRECATED: use TaskSourceSpec)
-type TaskSourceLocation struct {
-	ServerID    string
-	DiskID      uint32
-	CleanupType SourceCleanupType // What type of cleanup is needed
-}