feature: implement ipfs upload in worker

[noot]

• implement ipfs file upload in worker. previously, the file was being uploaded to s3 only. it's now uploaded to ipfs as well if the with_ipfs_upload config flag is supplied
• the file is found via cid, which contains the sha256 hash inside it, so it's fetchable given the hash (as you can deterministically reconstruct the cid)

[Copilot]

Pull Request Overview

This PR adds optional IPFS file upload support in the worker: when enabled via a CLI flag, files are uploaded to IPFS (in addition to S3). It refactors the file‐upload logic into dedicated functions and wires IPFS through the task bridge.

• Extracted S3 upload and signed‐URL retrieval into separate async functions and added an IPFS upload helper.
• Propagated an Option<Ipfs> through TaskBridge and CLI, with new --with-ipfs-upload and --ipfs-port flags.
• Updated Cargo manifests to include rust-ipfs, cid, and enabled tokio_unstable in CI.

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
crates/worker/src/docker/taskbridge/file_handler.rs	Factored S3+IPFS upload into handle_file_upload_s3 and handle_file_upload_ipfs, added IPFS flag
crates/worker/src/docker/taskbridge/bridge.rs	Added ipfs: Option<Ipfs> to config, threaded through TaskBridge and tests
crates/worker/src/cli/command.rs	Introduced with_ipfs_upload/ipfs_port args and IPFS node setup
crates/worker/Cargo.toml	Added workspace deps: rust-ipfs, cid
Cargo.toml	Added root deps: ipld-core, rust-ipfs, cid
.github/workflows/checks.yml	Enabled --cfg tokio_unstable for CI builds

Comments suppressed due to low confidence (2)

crates/worker/src/docker/taskbridge/file_handler.rs:109

• The new IPFS branch isn't covered by existing tests; add unit or integration tests that simulate with_ipfs_upload = true to verify handle_file_upload_ipfs logic.

    if let Some(ipfs) = ipfs {

crates/worker/src/cli/command.rs:122

• [nitpick] Add a doc comment above with_ipfs_upload (and ipfs_port) to explain its purpose, expected behavior, and any constraints.

        #[arg(long, default_value = "false")]