fix: v0.1.15 — production hardening (7 fixes)

Broker:
- Sweep stale presences (3 missed pings = disconnect, 30s interval)
- Exclude sender from broadcast fan-out + queue drain

CLI:
- Decrypt fallback: try base64 plaintext if crypto_box fails
- Stable session keypair across WS reconnects
- Peer name cache (30s TTL) instead of list_peers per push
- Clean up orphaned tmpdirs from crashed sessions (>1 hour old)
- Read displayName from config file (not just env var)

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

apps/cli/src/ws/client.ts

@@ -115,10 +115,12 @@ export class BrokerClient {
       const onOpen = async (): Promise<void> => {
         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;
+          // Only generate session keypair on first connect, not reconnects
+          if (!this.sessionPubkey) {
+            const sessionKP = await generateKeypair();
+            this.sessionPubkey = sessionKP.publicKey;
+            this.sessionSecretKey = sessionKP.secretKey;
+          }
 
           const { timestamp, signature } = await signHello(
             this.mesh.meshId,
@@ -376,6 +378,19 @@ export class BrokerClient {
             plaintext = null;
           }
         }
+        // Fallback: if direct decrypt failed, try plaintext base64 decode.
+        // This handles broadcasts and key mismatches gracefully.
+        if (plaintext === null && ciphertext) {
+          try {
+            const decoded = Buffer.from(ciphertext, "base64").toString("utf-8");
+            // Sanity check: valid UTF-8 text (not binary garbage)
+            if (/^[\x20-\x7E\s\u00A0-\uFFFF]*$/.test(decoded) && decoded.length > 0) {
+              plaintext = decoded;
+            }
+          } catch {
+            plaintext = null;
+          }
+        }
         const push: InboundPush = {
           messageId: String(msg.messageId ?? ""),
           meshId: String(msg.meshId ?? ""),