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/mremap.go

@@ -0,0 +1,57 @@
+// Copyright 2023 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 linux || netbsd
+
+package unix
+
+import "unsafe"
+
+type mremapMmapper struct {
+	mmapper
+	mremap func(oldaddr uintptr, oldlength uintptr, newlength uintptr, flags int, newaddr uintptr) (xaddr uintptr, err error)
+}
+
+var mapper = &mremapMmapper{
+	mmapper: mmapper{
+		active: make(map[*byte][]byte),
+		mmap:   mmap,
+		munmap: munmap,
+	},
+	mremap: mremap,
+}
+
+func (m *mremapMmapper) Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
+	if newLength <= 0 || len(oldData) == 0 || len(oldData) != cap(oldData) || flags&mremapFixed != 0 {
+		return nil, EINVAL
+	}
+
+	pOld := &oldData[cap(oldData)-1]
+	m.Lock()
+	defer m.Unlock()
+	bOld := m.active[pOld]
+	if bOld == nil || &bOld[0] != &oldData[0] {
+		return nil, EINVAL
+	}
+	newAddr, errno := m.mremap(uintptr(unsafe.Pointer(&bOld[0])), uintptr(len(bOld)), uintptr(newLength), flags, 0)
+	if errno != nil {
+		return nil, errno
+	}
+	bNew := unsafe.Slice((*byte)(unsafe.Pointer(newAddr)), newLength)
+	pNew := &bNew[cap(bNew)-1]
+	if flags&mremapDontunmap == 0 {
+		delete(m.active, pOld)
+	}
+	m.active[pNew] = bNew
+	return bNew, nil
+}
+
+func Mremap(oldData []byte, newLength int, flags int) (data []byte, err error) {
+	return mapper.Mremap(oldData, newLength, flags)
+}
+
+func MremapPtr(oldAddr unsafe.Pointer, oldSize uintptr, newAddr unsafe.Pointer, newSize uintptr, flags int) (ret unsafe.Pointer, err error) {
+	xaddr, err := mapper.mremap(uintptr(oldAddr), oldSize, newSize, flags, uintptr(newAddr))
+	return unsafe.Pointer(xaddr), err
+}