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/commands/launch.ts

@@ -11,7 +11,7 @@
  */
 
 import { spawn } from "node:child_process";
-import { mkdtempSync, writeFileSync, rmSync } from "node:fs";
+import { mkdtempSync, writeFileSync, rmSync, readdirSync, statSync } from "node:fs";
 import { tmpdir, hostname } from "node:os";
 import { join } from "node:path";
 import { createInterface } from "node:readline";
@@ -215,6 +215,17 @@ export async function runLaunch(extraArgs: string[]): Promise<void> {
   //    We just set the display name via env var.
   const displayName = args.name ?? `${hostname()}-${process.pid}`;
 
+  // Clean up orphaned tmpdirs from crashed sessions (older than 1 hour)
+  const tmpBase = tmpdir();
+  try {
+    for (const entry of readdirSync(tmpBase)) {
+      if (!entry.startsWith("claudemesh-")) continue;
+      const full = join(tmpBase, entry);
+      const age = Date.now() - statSync(full).mtimeMs;
+      if (age > 3600_000) rmSync(full, { recursive: true, force: true });
+    }
+  } catch { /* best effort */ }
+
   // 4. Write session config to tmpdir (isolates mesh selection).
   const tmpDir = mkdtempSync(join(tmpdir(), "claudemesh-"));
   const sessionConfig: Config = {