refactor: refactor task logic for better scalability (#76)

* refactor: a big refactor. wip

* refactor: port handle file

* refactor: place all handlers

* fix: task info nil pointer

* feat: enhance task progress tracking and context management

* feat: cancel task

* feat: stream mode

* feat: silent mode

* feat: dir cmd

* refactor: remove unused old file

* feat: rule cmd

* feat: handle silent mode

* feat: batch task

* fix: batch task progress and temp file cleanup

* refactor: update file creation and cleanup methods for better resource management

* feat: add save command with silent mode handling

* feat: message link

* feat: update message prompts to include file count in storage selection

* feat: slient save links

* refactor: reduce dup code

* feat: rule type

* feat: chose dir

* feat: refactor file handling and storage rules, improve error handling and logging

* feat: rule mode

* feat: telegraph pics

* fix: tphpics nil pointer and inaccurate dirpath

* feat: silent save telegraph

* feat: add suffix to avoid file overwrite

* feat: new storage telegram

* chore: tidy go mod

common/utils/dlutil/dl.go

@@ -0,0 +1,33 @@
+package dlutil
+
+import "time"
+
+var threadsLevels = []struct {
+	threads int
+	size    int64
+}{
+	{1, 10 << 20},
+	{2, 50 << 20},
+	{4, 200 << 20},
+	{8, 500 << 20},
+}
+
+func BestThreads(size int64, max int) int {
+	for _, thread := range threadsLevels {
+		if size < thread.size {
+			return min(thread.threads, max)
+		}
+	}
+	return max
+}
+
+func GetSpeed(downloaded int64, startTime time.Time) float64 {
+	if startTime.IsZero() {
+		return 0
+	}
+	elapsed := time.Since(startTime).Seconds()
+	if elapsed <= 0 {
+		return 0
+	}
+	return float64(downloaded) / elapsed
+}