chore: re-enable ruff in adk + langchain PR checks and fix lint debt

[mislavivanda]

Summary by cubic

Re-enabled ruff linting in PR CI for packages/adk-plugin and packages/langchain-data-analysis, added a ruff config to the langchain package, and cleaned up lint issues so CI passes.

• Dependencies

  • Added ruff config in packages/langchain-data-analysis/pyproject.toml (line length 100, selected rules, per-file ignores).
  • Bumped ruff to ^0.15.0.

• Refactors

  • Moved logger initialization below imports in packages/adk-plugin modules.
  • Reflowed long strings and function signatures in langchain_daytona_data_analysis/tools.py.
  • Minor test formatting updates to satisfy ruff.

^{Written for commit 417ae7c. Summary will update on new commits.}