fix(devframe): handle non-Error listen failures

The DF0052 catch assumed the caught value was an Error and cast both
`message` and `cause`. `listen()` can throw arbitrary values, so derive
the reason with the `error instanceof Error ? error.message : String(error)`
pattern already used at both DF0045 call sites in instance-registry.ts,
and pass the original value through as `cause` uncast.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: dvcolomban

packages/devframe/src/node/server.ts

@@ -272,7 +272,12 @@ export async function startHttpAndWs(options: StartHttpAndWsOptions): Promise<St
       // The WS transport is already attached above, so tear it down before
       // surfacing the failure rather than leaking it and its peers.
       await closeWs().catch(() => {})
-      throw diagnostics.DF0052({ host: bindHost, port, reason: (error as Error).message, cause: error as Error })
+      throw diagnostics.DF0052({
+        host: bindHost,
+        port,
+        reason: error instanceof Error ? error.message : String(error),
+        cause: error,
+      })
     }
   }