fix(workflows): standardize Python 3.12 across all Node.js builds

Unified Python version to 3.12 in build-smol.yml, build-sea.yml, and
build-wasm.yml. All three use gyp which has hashlib.md5() compatibility
issues with Python 3.13.

Verified Alpine 3.19 (Docker builds) ships Python 3.11.14 - not affected.

Python 3.13 error:
  TypeError: Strings must be encoded before hashing
  At: tools/gyp/pylib/gyp/generator/ninja.py:813

Author: jdalton

.github/workflows/build-sea.yml

@@ -335,7 +335,12 @@ jobs:
         if: steps.check-platform.outputs.should-run == 'true' && steps.yoga-cache-valid.outputs.valid != 'true' && matrix.os != 'windows'
         uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
         with:
-          python-version: '3.13.0'
+          # Use 3.12 instead of 3.13 - gyp has hashlib compatibility issues with 3.13.
+          # Error: TypeError: Strings must be encoded before hashing
+          # At: tools/gyp/pylib/gyp/generator/ninja.py:813 hashlib.md5(outputs[0])
+          # Python 3.13 requires .encode() for hashlib, but gyp doesn't support it yet.
+          # Alpine 3.19 (Docker builds) ships Python 3.11.14, not affected.
+          python-version: '3.12'
 
       - name: Cache Emscripten SDK (non-Windows)
         if: steps.check-platform.outputs.should-run == 'true' && steps.yoga-cache-valid.outputs.valid != 'true' && matrix.os != 'windows'

.github/workflows/build-smol.yml

@@ -346,6 +346,10 @@ jobs:
         uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
         with:
           # Use 3.12 instead of 3.13 - gyp has hashlib compatibility issues with 3.13.
+          # Error: TypeError: Strings must be encoded before hashing
+          # At: tools/gyp/pylib/gyp/generator/ninja.py:813 hashlib.md5(outputs[0])
+          # Python 3.13 requires .encode() for hashlib, but gyp doesn't support it yet.
+          # Alpine 3.19 (Docker builds) ships Python 3.11.14, not affected.
           python-version: '3.12'
 
       - name: Verify Python installation

.github/workflows/build-wasm.yml

@@ -204,7 +204,12 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@0b93645e9fea7318ecaed2b359559ac225c90a2b # v5.3.0
         with:
-          python-version: '3.13.0'
+          # Use 3.12 instead of 3.13 - gyp has hashlib compatibility issues with 3.13.
+          # Error: TypeError: Strings must be encoded before hashing
+          # At: tools/gyp/pylib/gyp/generator/ninja.py:813 hashlib.md5(outputs[0])
+          # Python 3.13 requires .encode() for hashlib, but gyp doesn't support it yet.
+          # Alpine 3.19 (Docker builds) ships Python 3.11.14, not affected.
+          python-version: '3.12'
 
       - name: Cache pip packages
         uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0