…d per-thread state (ggml-org#18976)

* Squashed commit of the following:

commit b3c6bf4
Author: Abhijit Ramesh <abhijitramesh2k@gmail.com>
Date:   Mon Dec 1 18:29:00 2025 -0800

    ggml webgpu: fix xielu parameter passing (ggml-org#11)

    The XIELU operation was incorrectly using static_cast to convert
    float parameters to uint32_t, which converted numeric values instead
    of preserving IEEE 754 bit patterns. This caused incorrect values
    to be interpreted by the GPU shader.

    * Use reinterpret_cast to preserve float bit patterns when passing
      through uint32_t params buffer
    * Update WGSL shader parameter types from u32 to f32
    * Re-enable XIELU support (was disabled due to numerical issues)

    Fixes NMSE test failures for XIELU operation on WebGPU backend.

commit 5ca9b5e
Author: neha-ha <137219201+neha-ha@users.noreply.github.com>
Date:   Tue Nov 18 12:17:00 2025 -0800

    Refactored pipelines and workgroup calculations (ggml-org#10)

    * refactored pipelines

    * refactored workgroup calculation

    * removed commented out block of prior maps

    * Clean up ceiling division pattern

    ---------

    Co-authored-by: Neha Abbas <nehaabbas@eduroam-169-233-141-223.ucsc.edu>
    Co-authored-by: Reese Levine <reeselevine1@gmail.com>

Author: James Contini <jamescontini@gmail.com>
Date:   Wed Oct 29 23:13:06 2025 -0700

    formatted embed wgsl and ggml-webgpu.cpp

commit e1f6bae
Author: James Contini <jamescontini@gmail.com>
Date:   Wed Oct 29 23:08:37 2025 -0700

    implemented REPL_Template support and removed bug in unary operators kernel

commit 8c70b8f
Author: James Contini <jamescontini@gmail.com>
Date:   Wed Oct 15 16:14:20 2025 -0700

    responded and dealt with PR comments

commit f9282c6
Author: James Contini <jamescontini@gmail.com>
Date:   Sun Oct 12 13:41:41 2025 -0700

    removed unnecesarry checking if node->src[1] exists for unary operators

commit 4cf28d7
Author: James Contini <jamescontini@gmail.com>
Date:   Sun Oct 12 13:32:45 2025 -0700

    All operators (inlcluding xielu) working

commit 74c6add
Author: James Contini <jamescontini@gmail.com>
Date:   Fri Oct 10 13:16:48 2025 -0700

    fixed autoconfig

commit 3627499
Author: James Contini <jamescontini@gmail.com>
Date:   Fri Oct 10 13:10:46 2025 -0700

    removed vestigial files

commit cb08583
Author: James Contini <jamescontini@gmail.com>
Date:   Fri Oct 10 12:59:32 2025 -0700

    abides by editor-config

commit 5360e28
Author: James Contini <jamescontini@gmail.com>
Date:   Fri Oct 10 12:45:57 2025 -0700

    rms_norm double declaration bug atoned

commit 7b09baa
Merge: 8a6ec84 74b8fc1
Author: James Contini <jamescontini@gmail.com>
Date:   Fri Oct 10 11:50:03 2025 -0700

    resolving merge conflicts

commit 8a6ec84
Author: James Contini <jamescontini@gmail.com>
Date:   Wed Oct 8 18:06:47 2025 -0700

    unary operators pass ggml tests

commit c3ae382
Author: James Contini <jamescontini@gmail.com>
Date:   Wed Oct 1 16:22:40 2025 -0700

    neg passes backend test

commit aa1c9b2
Author: James Contini <jamescontini@gmail.com>
Date:   Tue Sep 30 23:55:27 2025 -0700

    neg f16xf32xip builds and runs, havent actually ran a model that uses neg kernel yet though

Co-authored-by: James Contini <jamescontini@gmail.com>
Co-authored-by: Neha Abbas <neabbas@ucsc.edu>
Co-authored-by: Abhijit Ramesh <abhijitramesh2k@gmail.com>

* Remove extra code and format

* Add ops documentation (finally)

* ggml webgpu: add SOFTPLUS unary operator

Implements SOFTPLUS (log(1 + exp(x))) with f16/f32 support. Uses f32
precision for intermediate calculations to prevent f16 overflow.

* Add shader implementation and 4 variants (f32/f16, inplace/non-inplace)
* Register pipelines and device support
* Follow Vulkan backend numerical stability pattern

* ggml webgpu: add EXPM1 unary operator

Implements EXPM1 (exp(x) - 1) with f16/f32 support.

* Add shader implementation and 4 variants (f32/f16, inplace/non-inplace)
* Register pipelines and device support

* ggml webgpu: add FLOOR unary operator

Implements FLOOR (rounds down to nearest integer) with f16/f32 support.

* Add shader implementation and 4 variants (f32/f16, inplace/non-inplace)
* Register pipelines and device support

* ggml webgpu: add CEIL unary operator

Implements CEIL (rounds up to nearest integer) with f16/f32 support.

* Add shader implementation and 4 variants (f32/f16, inplace/non-inplace)
* Register pipelines and device support

* ggml webgpu: add ROUND unary operator

Implements ROUND (rounds to nearest integer) with f16/f32 support.

* Add shader implementation and 4 variants (f32/f16, inplace/non-inplace)
* Register pipelines and device support

* ggml webgpu: add TRUNC unary operator

Implements TRUNC (truncates towards zero) with f16/f32 support.

* Add shader implementation and 4 variants (f32/f16, inplace/non-inplace)
* Register pipelines and device support

* docs : update WebGPU support for unary operators (FLOOR, CEIL, ROUND, TRUNC, EXPM1, SOFTPLUS)

* Updates to webgpu get_memory

* Move shared state (webgpu_context) and device creation out of registration context, device context, and buffer context, and move into backend context

* Small cleanup

* Move Instance, Device, Adapter, Device creation, and capabilities to global state while moving Queue, pipelines, and buffers to per-thread state.

* Cleanups

* More cleanup

* Move staging_buf mutex to global context

* Resolve merge

* Resolve merge

* Resolve merge

* Clean up merge errors, delete forward declaration, and run clang-format

* Rename device_init to backend_init

* Move webgpu_context to backend_context

* Move buffer context members into global context and refactor function calls

* Run clang-format

* Remove commends

* Move parameter buffers to per-thread, add single memset_tensor param buf

* Fix CI compilation issue

* Fix builds for emscripten not supporting subgroups

* cleanup

* cleanup

---------

Co-authored-by: Reese Levine <reeselevine1@gmail.com>