Filecoin Pin: Unbounded DAG pinning can exhaust filecoin-pin server resources

Filecoin Pin is an IPFS Pinning Service API implementation that pins to Filecoin's PDP service. In daemon deployments up to and including version 1.1.0, `POST /pins` in `src/filecoin-pinning-server.ts` checks a caller-supplied CID with `CID.parse` and passes it to `pinStore.pin`, but does not enforce request rate limits or per-user quotas. In `src/filecoin-pin-store.ts`, each pin independently schedules `_processPinInBackground` with `setTimeout` without a queue, semaphore or concurrency cap, then recursively traverses the full DAG using `helia.pins.add(cid)`. The per-pin Helia/Bitswap node in `src/create-pinning-helia.ts` has no application-level byte, block or traversal-time limits. Blocks are written under `carStoragePath` by `src/core/car/car-blockstore-base.ts` and `src/core/car/car-file-backend.ts`, with `stats.totalSize` updated only after writing. An authenticated caller, or an anonymous caller when `ALLOW_NO_AUTH=true`, can submit large DAGs and exhaust disk, network, CPU, memory and libp2p resources, causing service degradation or host/process failure and leaving partial CAR files requiring recovery. The default localhost binding and token requirement reduce exposure. Because nodes have no bootstrap or mDNS configuration, a CID alone may not be fetchable, but caller-supplied `origins` can point to a reachable attacker-controlled libp2p source; concurrent requests accelerate resource pressure. Version 1.1.1 documents operational mitigations but does not implement the missing resource controls.