[Bug]: `com.atproto.sync.getBlob` hardcodes `https://bsky.network` (unreachable for non-`bsky.network` PDS)

[KC-2001MS]

Summary

ATProtoKit.getBlob(from:cid:) -> Data (ComAtprotoSyncGetBlobMethod.swift) sends its request to a hardcoded https://bsky.network. Blobs are served by the PDS, not the relay — the bsky.network relay/firehose carries repo records but not blob binaries. So getBlob fails for any account whose PDS host is not literally bsky.network, which is effectively all real accounts — including mainstream Bluesky accounts on *.host.bsky.network and third-party PDSes. The sibling getRepository(by:sinceRevision:) carries the same bsky.network hardcode, but there the relay mirrors the repo, so it succeeds in practice; the defect is only user-visible for getBlob. (Other PDS-served com.atproto.sync.* wrappers — getBlocks, listBlobs, getLatestCommit, getRepoStatus, sync.getRecord — share the same hardcode.)

Reproduction Steps

1. Authenticate with an account whose PDS host is not bsky.network (e.g. a mainstream *.host.bsky.network account, or a third-party PDS such as eurosky.social).
2. Call getBlob(from: did, cid: someCID) for a blob that exists on that account's PDS (e.g. the avatar CID from getProfile).
3. Observe the request goes to https://bsky.network/xrpc/com.atproto.sync.getBlob, which does not serve the blob, and the call fails.

Expected Results

The request routes to the PDS that hosts the blob — the session's serviceEndpoint for the caller's own data, or the DID-resolved PDS for an arbitrary did — the same precedence #296 introduced for describeRepository / listRecords (explicit pdsURL → DID resolution → existing host).

Actual Results

The method hardcodes the host:

// ComAtprotoSyncGetBlobMethod.swift
guard let requestURL = URL(string: "https://bsky.network/xrpc/com.atproto.sync.getBlob") else { ... }

There is no pdsURL parameter and no PDS resolution. Verified on-device against 3 accounts (*.host.bsky.network ×2 and eurosky.social): getBlob failed on all three, while getRepository succeeded (the relay mirrors repos, but not blobs).

What operating systems did you experience this bug?

macOS

Operating System Version

• macOS Tahoe 26.5.2
• iOS 26.5.2

ATProtoKit Version

0.33.3

Additional Context

Suggested fix: add an optional pdsURL and route through the existing resolvePDSHost(for:), matching describeRepository / listRecords. Precedence: explicit pdsURL → resolvePDSHost(for: accountDID) → self.pdsURL. The bsky.network literal is intentionally dropped rather than kept as a fallback: the relay never serves blobs, so it is never a useful host for getBlob.