cmd/age,tag: implement age1tagpq1.../p256mlkem768tag recipients

Test vectors generated from hpkewg/hpke-pq@19adaeb (hpkewg/hpke-pq#28 +
hpkewg/hpke-pq#32) and cfrg/draft-irtf-cfrg-concrete-hybrid-kems@1bbca40
(cfrg/draft-irtf-cfrg-concrete-hybrid-kems#16), plus the following diff:

diff --git a/reference-implementation/src/bin/generate.rs b/reference-implementation/src/bin/generate.rs
index 25e32e5..bc8f209 100644
--- a/reference-implementation/src/bin/generate.rs
+++ b/reference-implementation/src/bin/generate.rs
@@ -26,6 +26,15 @@ fn generate_test_vectors() -> TestVectors {
     // 5. QSF-P384-MLKEM1024 + SHAKE256 + AES-256-GCM
     vectors.push(TestVector:🆕:<QsfP384MlKem1024, Shake256, Aes256Gcm>());
 
+    vectors = TestVectors::new();
+
+    // age1pq - xwing
+    vectors.push(TestVector:🆕:<QsfX25519MlKem768, HkdfSha256, ChaChaPoly>());
+    // age1tag - p256tag
+    vectors.push(TestVector:🆕:<DhkemP256HkdfSha256, HkdfSha256, ChaChaPoly>());
+    // age1tagpq - p256mlkem768tag
+    vectors.push(TestVector:🆕:<QsfP256MlKem768, HkdfSha256, ChaChaPoly>());
+
     vectors
 }
 
diff --git a/reference-implementation/src/test_vectors.rs b/reference-implementation/src/test_vectors.rs
index 24335aa..4134fb5 100644
--- a/reference-implementation/src/test_vectors.rs
+++ b/reference-implementation/src/test_vectors.rs
@@ -369,6 +369,10 @@ impl TestVector {
             (0x0051, 0x0011, 0x0002) => self.v::<QsfP384MlKem1024, Shake256, Aes256Gcm>(),
             (0x0051, 0x0011, 0xffff) => self.v::<QsfP384MlKem1024, Shake256, ExportOnly>(),
 
+            // age pq combinations
+            (0x647a, 0x0001, 0x0003) => self.v::<QsfX25519MlKem768, HkdfSha256, ChaChaPoly>(),
+            (0x0050, 0x0001, 0x0003) => self.v::<QsfP256MlKem768, HkdfSha256, ChaChaPoly>(),
+
             _ => Err(format!(
                 "Unsupported algorithm combination: KEM={:#x}, KDF={:#x}, AEAD={:#x}",
                 self.kem_id, self.kdf_id, self.aead_id

cmd/age/parse.go

@@ -31,7 +31,7 @@ func (gitHubRecipientError) Error() string {
 
 func parseRecipient(arg string) (age.Recipient, error) {
 	switch {
-	case strings.HasPrefix(arg, "age1tag1"):
+	case strings.HasPrefix(arg, "age1tag1") || strings.HasPrefix(arg, "age1tagpq1"):
 		return tag.ParseRecipient(arg)
 	case strings.HasPrefix(arg, "age1") && strings.Count(arg, "1") > 1:
 		return plugin.NewRecipient(arg, pluginTerminalUI)