fix: vendor deps and fix CI go-version, timeout, GOTOOLCHAIN (HAN-414)

- Run go mod vendor to eliminate proxy.golang.org network dependency
- Set GOFLAGS=-mod=vendor at job env level so all go commands use vendor/
- Fix go-version from 1.23 to 1.24.0 to match go.mod
- Move GOTOOLCHAIN=local to job-level env (not per-step inline)
- Set cache: false on setup-go (cache is irrelevant with vendoring)
- Add timeout-minutes: 15 so failures are caught quickly instead of 3h

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

vendor/golang.org/x/sys/unix/gccgo.go

@@ -0,0 +1,59 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build gccgo && !aix && !hurd
+
+package unix
+
+import "syscall"
+
+// We can't use the gc-syntax .s files for gccgo. On the plus side
+// much of the functionality can be written directly in Go.
+
+func realSyscallNoError(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r uintptr)
+
+func realSyscall(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r, errno uintptr)
+
+func SyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr) {
+	syscall.Entersyscall()
+	r := realSyscallNoError(trap, a1, a2, a3, 0, 0, 0, 0, 0, 0)
+	syscall.Exitsyscall()
+	return r, 0
+}
+
+func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err syscall.Errno) {
+	syscall.Entersyscall()
+	r, errno := realSyscall(trap, a1, a2, a3, 0, 0, 0, 0, 0, 0)
+	syscall.Exitsyscall()
+	return r, 0, syscall.Errno(errno)
+}
+
+func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err syscall.Errno) {
+	syscall.Entersyscall()
+	r, errno := realSyscall(trap, a1, a2, a3, a4, a5, a6, 0, 0, 0)
+	syscall.Exitsyscall()
+	return r, 0, syscall.Errno(errno)
+}
+
+func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno) {
+	syscall.Entersyscall()
+	r, errno := realSyscall(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9)
+	syscall.Exitsyscall()
+	return r, 0, syscall.Errno(errno)
+}
+
+func RawSyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr) {
+	r := realSyscallNoError(trap, a1, a2, a3, 0, 0, 0, 0, 0, 0)
+	return r, 0
+}
+
+func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err syscall.Errno) {
+	r, errno := realSyscall(trap, a1, a2, a3, 0, 0, 0, 0, 0, 0)
+	return r, 0, syscall.Errno(errno)
+}
+
+func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err syscall.Errno) {
+	r, errno := realSyscall(trap, a1, a2, a3, a4, a5, a6, 0, 0, 0)
+	return r, 0, syscall.Errno(errno)
+}