refactor: pluginize text cleaning and tool NoMemory control

- SDK: ToolDef.NoMemory field, PluginSDK.RegisterTextCleaner/TextCleaners
- Registry: aggregate text cleaners from plugins, expose CleanText()
- Memory: replace hardcoded QQ regex CleanTemplateText with dynamic CleanText/SetTextCleaner
- StageHost: add ToolDef(name) lookup
- eventloop: check ToolDef.NoMemory before emitMemoryCandidate
- context/Prune: replace hardcoded agentcli/terminal source filter with ToolsUsed NoMemory check
- agentcli/cmd: mark tools with NoMemory: true
- main.go: wire memory.SetTextCleaner(pluginReg.CleanText)

internal/memory/clean_text_test.go

@@ -0,0 +1,83 @@
+package memory
+
+import (
+	"testing"
+)
+
+func TestCleanTextTrim(t *testing.T) {
+	prev := globalTextCleaner
+	globalTextCleaner = nil
+	defer func() { globalTextCleaner = prev }()
+
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"  hello  ", "hello"},
+		{"，hello", "hello"},
+		{"，，hello", "hello"},
+		{"  ，，hello  ", "hello"},
+		{"", ""},
+		{"   ", ""},
+		{"，", ""},
+		{"，x", "x"},
+	}
+	for _, tt := range tests {
+		got := CleanText(tt.input)
+		if got != tt.expected {
+			t.Errorf("CleanText(%q) = %q, want %q", tt.input, got, tt.expected)
+		}
+	}
+}
+
+func TestCleanTextWithRegisteredCleaner(t *testing.T) {
+	prev := globalTextCleaner
+	globalTextCleaner = func(text string) string {
+		return "prefix_" + text
+	}
+	defer func() { globalTextCleaner = prev }()
+
+	got := CleanText("  hello  ")
+	if got != "prefix_  hello" {
+		t.Errorf("CleanText with cleaner = %q, want %q", got, "prefix_  hello")
+	}
+}
+
+func TestCleanTextCleanerChain(t *testing.T) {
+	prev := globalTextCleaner
+	globalTextCleaner = func(text string) string {
+		text = text + "_step1"
+		text = text + "_step2"
+		return text
+	}
+	defer func() { globalTextCleaner = prev }()
+
+	got := CleanText("test")
+	if got != "test_step1_step2" {
+		t.Errorf("CleanText chain = %q, want %q", got, "test_step1_step2")
+	}
+}
+
+func TestSetTextCleanerReplace(t *testing.T) {
+	prev := globalTextCleaner
+	globalTextCleaner = func(text string) string { return "old_" + text }
+
+	SetTextCleaner(func(text string) string { return "new_" + text })
+	defer func() { globalTextCleaner = prev }()
+
+	got := CleanText("x")
+	if got != "new_x" {
+		t.Errorf("after SetTextCleaner = %q, want %q", got, "new_x")
+	}
+}
+
+func TestCleanTextEmptyAfterCleaner(t *testing.T) {
+	prev := globalTextCleaner
+	globalTextCleaner = func(text string) string { return "" }
+	defer func() { globalTextCleaner = prev }()
+
+	got := CleanText("something")
+	if got != "" {
+		t.Errorf("expected empty, got %q", got)
+	}
+}