feat: NoMemory/Cleaner memory system + doc update

- _sdk_local/ removed (moved to standalone sdk repo)
- internal/agent/core: NoMemory/Cleaner data-flow breakpoints
- internal/memory: clean_text, document store refactor
- internal/plugin/registry.go: plugin API alignment
- docs: PLUGIN_DEV.md, ARCHITECTURE.md NoMemory/Cleaner docs
- plan.md, review.md: status update

internal/memory/clean_text.go

@@ -6,17 +6,7 @@ import (
 	"gitcode.com/JianFeeeee/HomeAgent/internal/memory/vector"
 )
 
-var globalTextCleaner func(string) string
-
-func SetTextCleaner(fn func(string) string) {
-	globalTextCleaner = fn
-}
-
 func CleanText(text string) string {
-	if globalTextCleaner != nil {
-		text = globalTextCleaner(text)
-	}
-
 	text = strings.TrimSpace(text)
 
 	if text == "" {