Add D3D11 GPU texture sender API (0.1.4)

[clover0916]

Adds DirectXSender for D3D11 BGRA/RGBA texture sharing without an OpenGL context or CPU readback. NyanCast can publish received DJ video directly from its GPU pipeline.

The wrapper retains the supplied COM device, stays on its creating thread, rejects unsupported texture shapes/formats and device mismatches, and releases discovery registration on drop. The existing SpoutLibrary API remains available. Spout's static library uses the non-debug MSVC runtime to match Rust development builds. Version is 0.1.4, with usage and third-party notices included.

Updated autocxx to 0.30: its bindgen handles the Float16 types in current Windows/libclang headers that caused the old generator to panic. CI pins LLVM 20.1.8; local validation uses 22.1.1.

Validation:

• Windows CI passes cargo check and cargo test.
• Local library tests and cargo publish --dry-run pass.
• NyanCast integration covers D3D11 pixel channels/orientation, resolution changes, registration release/restart, wrong-device rejection, hidden software preview, and MediaFoundation/D3D11 preview.

The crates.io upload was attempted but rejected with HTTP 403 (authentication failed); publication requires refreshed credentials. NyanCast currently pins the Git commit.