fix(debug): hardware watchpoints, signal stops and breakpoint restore

Assisted-by: GLM 5.3

debug/tracer.go

@@ -12,10 +12,11 @@ type tracer interface {
 	Peek(addr uint64) (uint64, error)
 	Poke(addr uint64, val uint64) error
 	SetRegs(regs *Regs) error
+	Step() error
 	Pid() int
 }
 
-// mockTracer records Peek/Poke calls and provides fake register state.
+// mockTracer records Peek/Poke/Step calls and provides fake register state.
 type mockTracer struct {
 	mem   map[uint64]byte
 	peeks []uint64
@@ -23,7 +24,8 @@ type mockTracer struct {
 		addr uint64
 		val  uint64
 	}
-	regs *Regs
+	steps int
+	regs  *Regs
 }
 
 func newMockTracer() *mockTracer {
@@ -57,4 +59,8 @@ func (m *mockTracer) SetRegs(regs *Regs) error {
 	m.regs = regs
 	return nil
 }
+func (m *mockTracer) Step() error {
+	m.steps++
+	return nil
+}
 func (m *mockTracer) Pid() int { return 42 }