age,cmd/age,cmd/age-keygen: add post-quantum hybrid keys

doc/age-keygen.1.ronn

@@ -3,7 +3,7 @@ age-keygen(1) -- generate age(1) key pairs
 
 ## SYNOPSIS
 
-`age-keygen` [`-o` <OUTPUT>]<br>
+`age-keygen` [`-pq`] [`-o` <OUTPUT>]<br>
 `age-keygen` `-y` [`-o` <OUTPUT>] [<INPUT>]<br>
 
 ## DESCRIPTION
@@ -17,6 +17,11 @@ standard error.
 
 ## OPTIONS
 
+* `-pq`:
+    Generate a post-quantum hybrid ML-KEM-768 + X25519 key pair.
+
+    In the future, this might become the default.
+
 * `-o`, `--output`=<OUTPUT>:
     Write the identity to <OUTPUT> instead of standard output.
 
@@ -31,22 +36,29 @@ standard error.
 
 ## EXAMPLES
 
-Generate a new identity:
+Generate a new post-quantum identity:
+
+    $ age-keygen -pq
+    # created: 2025-11-17T13:39:06+01:00
+    # public key: age1pq167[... 1950 more characters ...]
+    AGE-SECRET-KEY-PQ-1K30MYPZAHAXHR22YHH27EGDVLU0QNSUH3DSV7J7NR3X6D9LHXNWSDLTV4T
+
+Generate a new traditional identity:
 
     $ age-keygen
     # created: 2021-01-02T15:30:45+01:00
     # public key: age1lvyvwawkr0mcnnnncaghunadrqkmuf9e6507x9y920xxpp866cnql7dp2z
     AGE-SECRET-KEY-1N9JEPW6DWJ0ZQUDX63F5A03GX8QUW7PXDE39N8UYF82VZ9PC8UFS3M7XA9
 
-Write a new identity to `key.txt`:
+Write a new post-quantum identity to `key.txt`:
 
     $ age-keygen -o key.txt
-    Public key: age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p
+    Public key: age1pq1cd[... 1950 more characters ...]
 
 Convert an identity to a recipient:
 
     $ age-keygen -y key.txt
-    age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p
+    age1pq1cd[... 1950 more characters ...]
 
 ## SEE ALSO