fix: resolve audit findings — stale text, dead code, build tags, docs

Assisted-by: MiMo V2.5 Pro

debug/breakpoint.go

@@ -1,6 +1,8 @@
 // Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
 // SPDX-License-Identifier: BSD-3-Clause
 
+//go:build linux
+
 package debug
 
 import "fmt"

debug/repl.go

@@ -94,7 +94,7 @@ func REPL(s *Session, bm *Breakpoints, codeBase uint64, funcOffset, funcSize, ar
 			text, instLen, _ := s.Disassemble(pc)
 			if strings.HasPrefix(strings.ToLower(text), "call") || strings.HasPrefix(strings.ToLower(text), "bl") {
 				afterAddr := pc + uint64(instLen)
-				bp, err := bm.Set(afterAddr, "(next)")
+				_, err := bm.Set(afterAddr, "(next)")
 				if err != nil {
 					fmt.Printf("cannot set next breakpoint: %v\n", err)
 					continue
@@ -109,7 +109,6 @@ func REPL(s *Session, bm *Breakpoints, codeBase uint64, funcOffset, funcSize, ar
 				}
 				bm.HandleTrap(&regs)
 				bm.Clear(afterAddr)
-				_ = bp
 			} else {
 				if err := s.Step(); err != nil {
 					fmt.Println(err)
@@ -130,7 +129,7 @@ func REPL(s *Session, bm *Breakpoints, codeBase uint64, funcOffset, funcSize, ar
 				fmt.Printf("cannot read return address: %v\n", err)
 				continue
 			}
-			bp, err := bm.Set(retAddr, "(finish)")
+			_, err = bm.Set(retAddr, "(finish)")
 			if err != nil {
 				fmt.Printf("cannot set finish breakpoint: %v\n", err)
 				continue
@@ -147,7 +146,6 @@ func REPL(s *Session, bm *Breakpoints, codeBase uint64, funcOffset, funcSize, ar
 				bm.HandleTrap(&regs)
 			}
 			bm.Clear(retAddr)
-			_ = bp
 			if s.Exited() {
 				fmt.Println("debuggee exited")
 			} else {

debug/tracer.go

@@ -1,6 +1,8 @@
 // Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
 // SPDX-License-Identifier: BSD-3-Clause
 
+//go:build linux
+
 package debug
 
 // tracer abstracts the minimal ptrace operations needed by the breakpoint