gh-145098: Run Apple Silicon macOS CI on macos-26 (Tahoe) (#145099)

.github/actionlint.yaml

diff --git a/.github/actionlint.yaml b/.github/actionlint.yaml
index eacfff2..3004466 100644
--- a/.github/actionlint.yaml
+++ b/.github/actionlint.yaml
@@ -1,3 +1,8 @@
+self-hosted-runner:
+  # Pending release of actionlint > 1.7.11 for macos-26-intel support
+  # https://github.com/rhysd/actionlint/pull/629
+  labels: ["macos-26-intel"]
+
 config-variables: null
 
 paths:

.github/workflows/build.yml

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a3898aa..3a6d6a7 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -198,16 +198,16 @@
     strategy:
       fail-fast: false
       matrix:
-        # macos-14 is M1, macos-15-intel is Intel.
-        # macos-15-intel only runs tests against the GIL-enabled CPython.
+        # macos-26 is Apple Silicon, macos-26-intel is Intel.
+        # macos-26-intel only runs tests against the GIL-enabled CPython.
         os:
-        - macos-14
-        - macos-15-intel
+        - macos-26
+        - macos-26-intel
         free-threading:
         - false
         - true
         exclude:
-        - os: macos-15-intel
+        - os: macos-26-intel
           free-threading: true
     uses: ./.github/workflows/reusable-macos.yml
     with:
@@ -336,7 +336,7 @@
       matrix:
         include:
           - arch: aarch64
-            runs-on: macos-14
+            runs-on: macos-26
           - arch: x86_64
             runs-on: ubuntu-24.04
 

.github/workflows/jit.yml

diff --git a/.github/workflows/jit.yml b/.github/workflows/jit.yml
index da9c75e..1a3fcb3 100644
--- a/.github/workflows/jit.yml
+++ b/.github/workflows/jit.yml
@@ -99,9 +99,9 @@
           - false
         include:
           - target: x86_64-apple-darwin/clang
-            runner: macos-15-intel
+            runner: macos-26-intel
           - target: aarch64-apple-darwin/clang
-            runner: macos-14
+            runner: macos-26
     steps:
       - uses: actions/checkout@v6
         with:

.github/workflows/reusable-macos.yml

diff --git a/.github/workflows/reusable-macos.yml b/.github/workflows/reusable-macos.yml
index 6afbf65..a96aab1 100644
--- a/.github/workflows/reusable-macos.yml
+++ b/.github/workflows/reusable-macos.yml
@@ -52,15 +52,15 @@
           --prefix=/opt/python-dev \
           --with-openssl="$(brew --prefix openssl@3.5)"
     - name: Build CPython
-      if : ${{ inputs.free-threading || inputs.os != 'macos-15-intel' }}
+      if : ${{ inputs.free-threading || inputs.os != 'macos-26-intel' }}
       run: gmake -j8
     - name: Build CPython for compiler warning check
-      if : ${{ !inputs.free-threading && inputs.os == 'macos-15-intel' }}
+      if : ${{ !inputs.free-threading && inputs.os == 'macos-26-intel' }}
       run: set -o pipefail; gmake -j8 --output-sync 2>&1 | tee compiler_output_macos.txt
     - name: Display build info
       run: make pythoninfo
     - name: Check compiler warnings
-      if : ${{ !inputs.free-threading && inputs.os == 'macos-15-intel' }}
+      if : ${{ !inputs.free-threading && inputs.os == 'macos-26-intel' }}
       run: >-
         python3 Tools/build/check_warnings.py
         --compiler-output-file-path=compiler_output_macos.txt

.github/workflows/tail-call.yml

diff --git a/.github/workflows/tail-call.yml b/.github/workflows/tail-call.yml
index 32c6aa7..88833ea 100644
--- a/.github/workflows/tail-call.yml
+++ b/.github/workflows/tail-call.yml
@@ -67,9 +67,9 @@
       matrix:
         include:
           - target: x86_64-apple-darwin/clang
-            runner: macos-15-intel
+            runner: macos-26-intel
           - target: aarch64-apple-darwin/clang
-            runner: macos-14
+            runner: macos-26
     steps:
       - uses: actions/checkout@v6
         with: