Fix TypeSpec Python regenerate workflow: apply README template from generated-tests branch layout

[Copilot]

The "Regenerate TypeSpec Python tests" job failed at the Apply README template step with Template README not found at eng/tools/azure-sdk-tools/emitter/generated/template/README.md. PR #47288 removed emitter/generated/ from main by design, leaving the template only on the typespec-python-generated-tests branch, but the workflow still expected it in the main checkout.

Changes

• .github/workflows/typespec-python-regenerate.yml — the workflow now stages regenerated azure and unbranded test packages in $RUNNER_TEMP, checks out the typespec-python-generated-tests branch layout, and applies the existing in-branch template/README.md directly:
  • Stage regenerated outputs before switching branches so they are preserved safely
  • Check out the source branch from typespec-python-generated-tests before copying regenerated files into eng/tools/azure-sdk-tools/emitter/generated
  • Reuse eng/tools/azure-sdk-tools/emitter/generated/template/README.md from that branch layout instead of fetching the template into a temp file
  • Update the missing-branch error message to clarify that the generated-tests branch history must contain the template path
  • Harden cleanup of the staged temp directory

GENERATED_STAGE_DIR="${RUNNER_TEMP}/typespec-python-generated"
cp -r "_typespec/packages/http-client-python/tests/generated/azure" "$GENERATED_STAGE_DIR/azure"
cp -r "_typespec/packages/http-client-python/tests/generated/unbranded" "$GENERATED_STAGE_DIR/unbranded"

git fetch --no-tags --depth=1 origin "$TARGET_BRANCH"
git checkout -B "$SOURCE_BRANCH" "origin/$TARGET_BRANCH"

cp -r "$GENERATED_STAGE_DIR/azure" "$TARGET/azure"
cp -r "$GENERATED_STAGE_DIR/unbranded" "$TARGET/unbranded"

TEMPLATE="$TARGET/template/README.md"
find "$TARGET" -type f -name README.md \
  ! -path "$TARGET/README.md" \
  ! -path "$TARGET/template/*" \
  -print -exec cp -f "$TEMPLATE" {} \;

[Copilot]

Pull request overview

This PR fixes the TypeSpec Python test regeneration workflow by sourcing the README template from the typespec-python-generated-tests branch (where it now lives after PR #47288), rather than expecting it to exist in the main checkout.

Changes:

• Update the “Apply README template” step to git fetch the typespec-python-generated-tests branch and git show the template into a temporary file.
• Improve the failure message to indicate the branch/path to check when the template can’t be retrieved.
• Clean up the temporary README template file after copying.

[Copilot]

Pull request overview

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