fix(spm): sync Package.swift checksums to v0.19.13 binaries

After v0.19.13 was tagged, the release.yml built the binaries and
uploaded them to the v0.19.13 release. The checksums in Package.swift
at the v0.19.13 tag commit were the v0.19.12 checksums (because Package.swift
is updated BEFORE the binaries exist — a bootstrap limitation of the
non-deterministic Xcode builds).

This PR updates Package.swift with v0.19.13's actual binary checksums so
SPM consumers pinning to main get matching binaries. Tag v0.19.13 itself
will still have stale checksums — consumers using `from: "0.19.13"` via
SPM need to wait for v0.19.14 (or pin to branch main).

No version bump — this is a pure checksum sync, not a new release.

Actual v0.19.13 checksums:
  RACommons-ios-v0.19.13.zip:       a1caaf12...
  RABackendLLAMACPP-ios-v0.19.13.zip: 7ff978fb...
  RABackendONNX-ios-v0.19.13.zip:    0f857555...

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sanchitmonga22

Package.swift

@@ -335,17 +335,17 @@ func binaryTargets() -> [Target] {
             .binaryTarget(
                 name: "RACommonsBinary",
                 url: "https://github.com/RunanywhereAI/runanywhere-sdks/releases/download/v\(sdkVersion)/RACommons-ios-v\(sdkVersion).zip",
-                checksum: "189bcf6cf844d1df1ce51ebdf396f7b7ec24aeb5c9c3965e70c5e3851a0d8fb3"
+                checksum: "a1caaf12186c896b49bfccc7348a71c3b3428b282e5ac3f5a3181a022b5401da"
             ),
             .binaryTarget(
                 name: "RABackendLlamaCPPBinary",
                 url: "https://github.com/RunanywhereAI/runanywhere-sdks/releases/download/v\(sdkVersion)/RABackendLLAMACPP-ios-v\(sdkVersion).zip",
-                checksum: "283632cd5fc8c76bbafc42a0dcfbd8a2039591e022c33eadf18fcab336ec006c"
+                checksum: "7ff978fbc87726423c682298f04354c7c11dfbfe9403b51f63d49df9c92e097a"
             ),
             .binaryTarget(
                 name: "RABackendONNXBinary",
                 url: "https://github.com/RunanywhereAI/runanywhere-sdks/releases/download/v\(sdkVersion)/RABackendONNX-ios-v\(sdkVersion).zip",
-                checksum: "64404b1b53f82399a9053a323d05b22c6a9e153d7ecefc25f9d9e67d67996a53"
+                checksum: "0f8575559ac96a9a7b872bb3adca3608acef38fdec1ab8ccf9b0716a8d627c6c"
             ),
         ]