Build and test conda packages and wheels

Adds a ci/ directory and .github/workflows/intel-ci.yml, which build the
conda packages and the wheels for every declared platform and Python and
test each with ci/test.py on the OpenCL CPU device.

conda-recipe/ is now the only recipe, the conda-forge one that was
conda-recipe-cf/; the Intel-channel recipe and conda-package.yml are
removed. The dev uploads to anaconda.org and their cleanup move into
intel-ci.yml, for pushes to master and tags only. The wheels leave the SYCL
runtime out and require intel-sycl-rt and intel-cmplr-lib-rt, as the PyPI
wheels do; scikit-build is pinned below 1.0 (#2341).

LDFLAGS in the cibuildwheel environment links every Linux library with
-z,relro,-z,now, as conda-forge's compiler activation does for the conda
packages, so libDPCTLSyclInterface.so gets full RELRO like the extensions.
conda-build gets --extra-meta remote_url=... sha=... when GitHub Actions
sets GITHUB_SERVER_URL, GITHUB_REPOSITORY and GITHUB_SHA, so each conda
package records the commit it was built from.

A pull request also builds and tests the newest free-threaded version, and
every push and tag run gets a concurrency group of its own. The benchmarks
take PyYAML from conda-forge, as PyPI has no Python 3.15 wheel for it yet.
ci/build.py refuses two built packages with the same file name, which would
overwrite each other in its flat output directory.

Author: jharlow-intel

.github/workflows/conda-package-cf.yml

@@ -13,7 +13,7 @@ env:
   PACKAGE_NAME: dpctl
   MODULE_NAME: dpctl
   TEST_ENV_NAME: test_dpctl
-  RECIPE_DIR: conda-recipe-cf
+  RECIPE_DIR: conda-recipe
   CHANNELS: "-c conda-forge --override-channels"
   VER_SCRIPT1: "import json; f = open('ver.json', 'r'); j = json.load(f); f.close(); d = j['dpctl'][0];"
   VER_SCRIPT2: "print('='.join((d[s] for s in ('version', 'build'))))"
@@ -60,7 +60,7 @@ jobs:
         with:
           path: ~/.conda/pkgs
           key:
-            ${{ runner.os }}-conda-cf-${{ env.CACHE_NUMBER }}-python-${{ matrix.python }}-spec-${{ matrix.python == '3.14' && contains(matrix.python_spec, 'cp314t') && 't' || '' }}-${{hashFiles('conda-recipe-cf/meta.yaml') }}
+            ${{ runner.os }}-conda-cf-${{ env.CACHE_NUMBER }}-python-${{ matrix.python }}-spec-${{ matrix.python == '3.14' && contains(matrix.python_spec, 'cp314t') && 't' || '' }}-${{hashFiles('conda-recipe/meta.yaml') }}
           restore-keys: |
             ${{ runner.os }}-conda-cf-${{ env.CACHE_NUMBER }}-python-${{ matrix.python }}-spec-${{ matrix.python == '3.14' && contains(matrix.python_spec, 'cp314t') && 't' || '' }}-
             ${{ runner.os }}-conda-cf-${{ env.CACHE_NUMBER }}-
@@ -405,7 +405,7 @@ jobs:
       EXAMPLES_ENV_NAME: examples
       BUILD_ENV_NAME: build_env
       DPCPP_CMPLR: "dpcpp_linux-64>=2026.0"
-      # keep in sync with conda-recipe-cf/conda_build_config.yaml
+      # keep in sync with conda-recipe/conda_build_config.yaml
       GCC_CMPLR_VERSION: '15'
 
     steps: