ArasanEmbedded 1.6.0

ArasanEmbedded 1.6.0 refreshes Arasan to upstream 99adddfbc73c4f51c8f9c068439d0844863dd2e9 (v26.1-49-g99adddf) and adopts its version-11 neural network.

• Includes forty-five upstream commits since the preceding snapshot, adding pawn-pair and threat features, compressed network weights, and Apple-arm64 NEON optimizations.
• Bundles arasanv11-20261105.nnue (36,367,668 bytes; SHA-256 cf48f3ff5dced6166d3bc49b7bb54e4d7bb9b0543b2747baefeda7679bfaee6d). Default clients receive the matching resource automatically. Clients supplying an NNUE file must replace their version-8 asset with the matching version-11 resource.
• Updates the explicit native source list and Swift/native model preflights together. Preserves the existing stream-input integration, package-owned global initializer, 4 MiB engine-thread stack and Fathom revision.
• Leaves the public Swift API unchanged; compatibility against 1.5.0 passed.

Validation: the complete local gate passed, including the 60-test suite under Debug, Release and Thread Sanitizer, CLI smoke/soak, constrained-stack startup, iOS simulator and generic-device builds, and public API compatibility. The optional downloaded Syzygy fixture test also passed. Required notices and source-archive asset policy were verified. SwiftChessDemo's candidate passed 111 non-UI tests and all 36 simulator GUI tests with the updated engines; physical-device checks were not repeated.

This is a source-only release with no prebuilt app, framework or engine attached. The required NNUE file remains a tracked SwiftPM data resource, as in prior releases. Arasan, wrapper and Fathom license notices are retained.