Extract self-hosted runner jobs from build.yml into a dedicated
build-self-hosted.yml following the llama.cpp pattern:
  - gpu-cuda (NVIDIA Linux)
  - gpu-vulkan-nvidia-cm (NVIDIA Linux)
  - gpu-vulkan-nvidia-cm2 (NVIDIA Linux + COOPMAT2)
  - gpu-metal (macOS ARM64)
  - gpu-vulkan (macOS ARM64)

GitHub-hosted CPU jobs remain in build.yml.

Assisted-by: llama.cpp:local pi

Extract release-related jobs from build.yml into a dedicated
release.yml following the llama.cpp pattern:
  - determine-tag
  - windows (Win32/x64, SDL2)
  - windows-blas (Win32/x64, OpenBLAS)
  - windows-cublas (x64, CUDA 11.8/12.4)
  - ios-xcode-build
  - bindings-java (depends on windows)
  - release (artifact aggregation + GitHub release)

CoreML job stays in build.yml with its own local tag calculation.

Assisted-by: llama.cpp:local pi

Assisted-by: llama.cpp:local pi

This commit adds the --fail option to the model download scripts so that
if the model download returns a server error this is picked up. This is
then detected in run.sh and a error message is displayed and the script
stops and returns an error.

The motivation for this is that currently it is possible for the model
download to fail but this script proceeds and instead of a model file
the contents will be an html page probably with the error. This will
then cause the model to not be able to load due to a missing magic
number. I'm not sure we can do much about the downloading failing,
perhaps a retry but at least this will give a clearer error message.

Refs: https://github.com/danbev/whisper.cpp/actions/runs/26866349389/job/79230794512

This commit adds curl retry options to the model download script.

The motivation is that currently when CI jobs run huggingface rate limit
the requests and return:
```console
curl: (22) The requested URL returned error: 429
```
This is an attempt to work around this and if it does not work then we
can an authorization token.

This job has been commented out as it has been flaky in the past. I'll
monitor this and if it continues to be unreliable we can disable it in
the github actions GUI instead of commenting it out like we did before.

The ccache will only be saved on pushed to master.

The motivation for this is that the save parameter does not seem to work
with the current version.

This commit remove build-linux.yml as the same jobs are also run by
build-gcc.yml, with the exception that build-gcc.yml also run ctest).
So keeping build-gcc.yml and removing the redundant build-linux.yml.

This is currently causing the following failure:
```console
sccache C:\PROGRA~1\NVIDIA~1\CUDA\v\bin\nvcc.exe -forward-unknown-to-host-compiler -DGGML_BACKEND_BUILD -DGGML_BACKEND_SHARED -DGGML_CUDA_PEER_MAX_BATCH_SIZE=128 -DGGML_SCHED_MAX_COPIES=4 -DGGML_SHARED -D_CRT_SECURE_NO_WARNINGS -D_XOPEN_SOURCE=600 -Dggml_cuda_EXPORTS -DCMAKE_INTDIR=\"Release\" -ID:\a\whisper.cpp\whisper.cpp\ggml\src\ggml-cuda\.. -ID:\a\whisper.cpp\whisper.cpp\ggml\src\..\include -isystem "C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v\include" -Xcompiler="-MD -O2 -Ob2" -DNDEBUG -std=c++17 -arch=native -use_fast_math -extended-lambda -Xcompiler /Zc:preprocessor -MD -MT ggml\src\ggml-cuda\CMakeFiles\ggml-cuda.dir\Release\allreduce.cu.obj -MF ggml\src\ggml-cuda\CMakeFiles\ggml-cuda.dir\Release\allreduce.cu.obj.d -x cu -c D:\a\whisper.cpp\whisper.cpp\ggml\src\ggml-cuda\allreduce.cu -o ggml\src\ggml-cuda\CMakeFiles\ggml-cuda.dir\Release\allreduce.cu.obj -Xcompiler=-Fdggml\src\ggml-cuda\CMakeFiles\ggml-cuda.dir\Release\,-FS
sccache: encountered fatal error
sccache: error: Could not parse shell line
sccache: caused by: Could not parse shell line
```

Refs: https://github.com/danbev/whisper.cpp/actions/runs/26883673904/job/79290017353

This commit removes the tag form the linux release artifacts to be
consistent with the existing artifacts.

If we want to include the tag then we can do that in a follow-up PR.