chore: regenerate libraries with gapic-generator v1.38.0

[hebaalazzeh]

Description

Regenerates all packages and preview-packages with gapic-generator v1.38.0 via librarian generate --all.

Stacked on top of #18057

Steps to Reproduce the Full Regeneration Diff

1. Prerequisites & Environment Setup

Ensure Go, Python 3.11+, and protoc (libprotoc 33.1 / 33.5) are installed and available in your $PATH:

# Verify protoc version
protoc --version

# Create and activate a Python virtual environment
python3 -m venv .venv
source .venv/bin/activate

# Install synthtool in the environment
pip install synthtool

2. Clean Locks, Synthtool Cache, & Export Template Directory

Synthtool caches templates locally under ~/.cache/synthtool/synthtool. Clear any stale locks, ensure a clean template clone, and export the template path:

# Remove any stale git locks if present
rm -f .git/index.lock
rm -f "$HOME/.cache/synthtool/synthtool/.git/index.lock"

# Clean existing synthtool cache
rm -rf "$HOME/.cache/synthtool/synthtool"

# Clone the latest synthtool repository
git clone https://github.com/googleapis/synthtool.git "$HOME/.cache/synthtool/synthtool"

# Export the templates path required by synthtool
export SYNTHTOOL_TEMPLATES="$HOME/.cache/synthtool/synthtool/synthtool/gcp/templates"

3. Clean Stale Workspace Artifacts

Remove any temporary build/staging directories left over from previous runs:

rm -rf packages/*/tmp preview-packages/*/tmp

4. Install Dependencies via Librarian

Install the exact tool versions specified in librarian.yaml (including gapic-generator 1.38.0, formatters, and linters):

go run github.com/googleapis/librarian/cmd/librarian@v0.31.0 install

5. Run Librarian Generation

Run librarian to regenerate all packages across the repository:

go run github.com/googleapis/librarian/cmd/librarian@v0.31.0 generate --all

6. Post-Generation Cleanup

Remove temporary staging artifacts:

rm -rf packages/*/tmp preview-packages/*/tmp

[gemini-code-assist]

Code Review

This pull request bumps the google-api-core dependency version to 2.28.0 across various integration configurations and updates the gapic-generator tool to version 1.38.0. In the google-ads-admanager package, a new compatibility module _compat.py is introduced to handle request transcoding and endpoint resolution. Consequently, the generated REST transport classes are refactored to utilize this shared module, removing redundant inline transcoding helper methods and significantly cleaning up the codebase. As there are no review comments, no additional feedback is provided.

[quirogas]

Please add the steps to generate this diff for posterity.

[hebaalazzeh]

Please add the steps to generate this diff for posterity.

added in PR comment