fix(acp): cursor resume bricked by 16MiB ACP wire-message cap

Cursor ACP resume fails permanently once a session emits a single JSON-RPC line over 16 MiB.

Repro: a thread whose cursor session stored large tool results (in our case two ~30MB StrReplace results embedding the cursor-agent bundle diff, store.db 93MB + 31MB WAL). Every retry fails before the prompt, at session/set_config_option during startSession and at session/prompt during sendTurn:

ProviderAdapterRequestError (cursor) for session/set_config_option: ACP protocol operation 'decode-wire-message' failed caused by MaxBufferSizeExceeded: RPC serialization buffer exceeded the maximum size of 16777216.

Root: packages/effect-acp/src/protocol.ts uses RpcSerialization.ndJsonRpc() with the Effect default (16 * 1024 * 1024). Reinstalling/fixing the cursor CLI does not help because the history persists in ~/.cursor/acp-sessions/<sessionId>/store.db and is replayed on every resume, so the thread is unrecoverable without detaching resumeCursor.

Expected: raise the ACP ndjson framing cap (e.g. 64MiB) so large but legitimate agent payloads resume instead of bricking the thread.

Start in packages/effect-acp/src/protocol.ts and inspect the RpcSerialization.ndJsonRpc configuration and its 16 MiB default. Reproduce the ACP resume path with a payload larger than 16 MiB, then verify that sessions containing large stored tool results can pass session/set_config_option and session/prompt without decode-wire-message failure.