feat: v0.1.10 — per-session ephemeral keypairs

Each WS connection generates its own ed25519 keypair (sessionPubkey)
sent in the hello handshake. The broker stores it on the presence
row and uses it for message routing + list_peers. This gives every
`claudemesh launch` a unique crypto identity without burning invite
uses — member auth stays permanent, session identity is ephemeral.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/cli/src/ws/client.ts

@@ -21,6 +21,7 @@ import {
   isDirectTarget,
 } from "../crypto/envelope";
 import { signHello } from "../crypto/hello-sig";
+import { generateKeypair } from "../crypto/keypair";
 
 export type Priority = "now" | "next" | "low";
 export type ConnStatus = "connecting" | "open" | "closed" | "reconnecting";
@@ -74,6 +75,8 @@ export class BrokerClient {
   private pushHandlers = new Set<PushHandler>();
   private pushBuffer: InboundPush[] = [];
   private listPeersResolvers: Array<(peers: PeerInfo[]) => void> = [];
+  private sessionPubkey: string | null = null;
+  private sessionSecretKey: string | null = null;
   private closed = false;
   private reconnectAttempt = 0;
   private helloTimer: NodeJS.Timeout | null = null;
@@ -109,8 +112,13 @@ export class BrokerClient {
 
     return new Promise<void>((resolve, reject) => {
       const onOpen = async (): Promise<void> => {
-        this.debug("ws open → signing + sending hello");
+        this.debug("ws open → generating session keypair + signing hello");
         try {
+          // Generate per-session ephemeral keypair for message routing.
+          const sessionKP = await generateKeypair();
+          this.sessionPubkey = sessionKP.publicKey;
+          this.sessionSecretKey = sessionKP.secretKey;
+
           const { timestamp, signature } = await signHello(
             this.mesh.meshId,
             this.mesh.memberId,
@@ -123,6 +131,7 @@ export class BrokerClient {
               meshId: this.mesh.meshId,
               memberId: this.mesh.memberId,
               pubkey: this.mesh.pubkey,
+              sessionPubkey: this.sessionPubkey,
               displayName: process.env.CLAUDEMESH_DISPLAY_NAME || undefined,
               sessionId: `${process.pid}-${Date.now()}`,
               pid: process.pid,
@@ -203,7 +212,7 @@ export class BrokerClient {
       const env = await encryptDirect(
         message,
         targetSpec,
-        this.mesh.secretKey,
+        this.sessionSecretKey ?? this.mesh.secretKey,
       );
       nonce = env.nonce;
       ciphertext = env.ciphertext;
@@ -349,7 +358,7 @@ export class BrokerClient {
           plaintext = await decryptDirect(
             { nonce, ciphertext },
             senderPubkey,
-            this.mesh.secretKey,
+            this.sessionSecretKey ?? this.mesh.secretKey,
           );
         }
         // Legacy/broadcast path: no senderPubkey means the message