feat: AutoZero 通用 Agent 框架（从 AutoGo 五阶段拆分完成）

llm（三协议 Provider）/ session（JSONL 持久化）/ tools（Registry、围栏、
builtin、computer）/ cdp（browser）/ skills / mcp / agent（循环、两级压缩、
编排、审批门控）+ 底座 jsonl/textx/execx/diag/scratch/spill/imagecache。

产品装配代码（config 桥接、schedule 工具、memory/plan/retro/prompt）
留在 AutoGo，宿主接入方式见 MIGRATION.md。

tools/computer_test.go

@@ -0,0 +1,105 @@
+package tools
+
+import (
+	"context"
+	"testing"
+)
+
+// TestComputerValidation：参数校验失败必须发生在任何真实 GUI 调用之前
+// （三平台通用：错误先行，即使依赖缺失也应报校验错——实际上 Linux/Windows
+// 上 Available() 先失败也是合法错误，本测试在任一平台都应通过）。
+func TestComputerValidation(t *testing.T) {
+	c := Computer()
+	cases := []string{
+		`{"action":"bogus"}`,
+		`{"action":"left_click"}`,      // 缺坐标
+		`{"action":"type"}`,            // 缺文本
+		`{"action":"key","key":"cmd"}`, // 无主键
+		`{`,
+	}
+	for _, in := range cases {
+		if _, err := c.Run(context.Background(), in); err == nil {
+			t.Fatalf("input %q should fail", in)
+		}
+	}
+}
+
+func TestParseChord(t *testing.T) {
+	mods, main, err := parseChord("cmd+shift+t")
+	if err != nil || main != "t" || len(mods) != 2 || mods[0] != "cmd" || mods[1] != "shift" {
+		t.Fatalf("cmd+shift+t: mods=%v main=%q err=%v", mods, main, err)
+	}
+	if _, main, _ := parseChord("ENTER"); main != "enter" {
+		t.Fatalf("case normalization failed: %q", main)
+	}
+	for _, bad := range []string{"", "cmd", "cmd+a+b", "cmd++q", "foo", "ctrl+enter+esc"} {
+		if _, _, err := parseChord(bad); err == nil {
+			t.Fatalf("%q should be rejected", bad)
+		}
+	}
+}
+
+func TestChordToXdotool(t *testing.T) {
+	cases := []struct{ in, want string }{
+		{"ctrl+c", "ctrl+c"},
+		{"cmd+c", "super+c"},
+		{"ctrl+alt+delete", "ctrl+alt+BackSpace"},
+		{"pageup", "Page_Up"},
+		{"cmd+shift+t", "super+shift+t"},
+		{"enter", "Return"},
+		{"space", "space"},
+		{"a", "a"},
+	}
+	for _, c := range cases {
+		mods, main, err := parseChord(c.in)
+		if err != nil {
+			t.Fatalf("%s: %v", c.in, err)
+		}
+		got, err := chordToXdotool(mods, main, c.in)
+		if err != nil || got != c.want {
+			t.Fatalf("%s: got %q (%v), want %q", c.in, got, err, c.want)
+		}
+	}
+	if _, err := chordToXdotool([]string{"fn"}, "a", "fn+a"); err == nil {
+		t.Fatal("fn should be rejected on Linux")
+	}
+}
+
+func TestChordToSendKeys(t *testing.T) {
+	cases := []struct{ in, want string }{
+		{"ctrl+c", "^c"},
+		{"alt+f4", "%{F4}"},
+		{"ctrl+shift+esc", "^+{ESC}"},
+		{"enter", "{ENTER}"},
+		{"pageup", "{PGUP}"},
+		{"ctrl+{", "^{{}"},
+		{"a", "a"},
+	}
+	for _, c := range cases {
+		mods, main, err := parseChord(c.in)
+		if err != nil {
+			t.Fatalf("%s: %v", c.in, err)
+		}
+		got, err := chordToSendKeys(mods, main, c.in)
+		if err != nil || got != c.want {
+			t.Fatalf("%s: got %q (%v), want %q", c.in, got, err, c.want)
+		}
+	}
+	for _, bad := range []string{"cmd+c", "win+r", "fn+left"} {
+		mods, main, err := parseChord(bad)
+		if err != nil {
+			t.Fatalf("%s: %v", bad, err)
+		}
+		if _, err := chordToSendKeys(mods, main, bad); err == nil {
+			t.Fatalf("%s should be rejected on Windows", bad)
+		}
+	}
+}
+
+func TestSendKeysEscape(t *testing.T) {
+	got := sendKeysEscape("a+b\nc{d}\t]")
+	want := "a{+}b{ENTER}c{{}d{}}{TAB}{]}"
+	if got != want {
+		t.Fatalf("got %q want %q", got, want)
+	}
+}