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/github.com/miekg/dns/reverse.go

@@ -0,0 +1,55 @@
+package dns
+
+// StringToType is the reverse of TypeToString, needed for string parsing.
+var StringToType = reverseInt16(TypeToString)
+
+// StringToClass is the reverse of ClassToString, needed for string parsing.
+var StringToClass = reverseInt16(ClassToString)
+
+// StringToOpcode is a map of opcodes to strings.
+var StringToOpcode = reverseInt(OpcodeToString)
+
+// StringToRcode is a map of rcodes to strings.
+var StringToRcode = reverseInt(RcodeToString)
+
+func init() {
+	// Preserve previous NOTIMP typo, see github.com/miekg/dns/issues/733.
+	StringToRcode["NOTIMPL"] = RcodeNotImplemented
+}
+
+// StringToAlgorithm is the reverse of AlgorithmToString.
+var StringToAlgorithm = reverseInt8(AlgorithmToString)
+
+// StringToHash is a map of names to hash IDs.
+var StringToHash = reverseInt8(HashToString)
+
+// StringToCertType is the reverse of CertTypeToString.
+var StringToCertType = reverseInt16(CertTypeToString)
+
+// StringToStatefulType is the reverse of StatefulTypeToString.
+var StringToStatefulType = reverseInt16(StatefulTypeToString)
+
+// Reverse a map
+func reverseInt8(m map[uint8]string) map[string]uint8 {
+	n := make(map[string]uint8, len(m))
+	for u, s := range m {
+		n[s] = u
+	}
+	return n
+}
+
+func reverseInt16(m map[uint16]string) map[string]uint16 {
+	n := make(map[string]uint16, len(m))
+	for u, s := range m {
+		n[s] = u
+	}
+	return n
+}
+
+func reverseInt(m map[int]string) map[string]int {
+	n := make(map[string]int, len(m))
+	for u, s := range m {
+		n[s] = u
+	}
+	return n
+}