Resolves#9420 (critical memory usage issue in PROD deployment)
When the plugin's ExecuteCodeTaskHandler returns a Uint8Array (e.g. from penpotUtils.exportImage),
JSON.stringify previously serialized it as an object with numeric string keys,
causing ~10x payload expansion and large peak heap usage on the server side.
The plugin now wraps a top-level Uint8Array result in a tagged envelope
{ __type: "base64", data: <base64> }, and ImageContent.byteData decodes this envelope
on the server. The legacy numeric-keyed-object path is retained as a fallback for
compatibility with older plugin builds.
The ping interval was stored in a single variable shared across all
WebSocket connections, so each new connection overwrote the previous
handle and leaked the prior interval.
Move the interval onto ClientConnection as a per-connection field,
and centralize teardown in a new removeConnection(ws) method used
by the close, error and duplicate token rejection paths.
Resolves#9430
The ReplServer Express app was calling `app.listen(port)` with no host
argument, causing Node/Express to default to binding on all interfaces
(0.0.0.0). Combined with the unauthenticated /execute endpoint, any
network peer could POST arbitrary JS and get it run inside the MCP
process.
Fix: add a `host` parameter (default "localhost") to the ReplServer
constructor and pass it to `app.listen`. The call site in
PenpotMcpServer now forwards `this.host` (sourced from
PENPOT_MCP_SERVER_HOST env var, default "localhost"), so environment-
variable overrides continue to work.
Signed-off-by: Andrey Antukh <niwi@niwi.nz>