This PR consolidates development tooling and CI workflows from the individual project repos into a monorepo-compatible format at the top level.

Changes

Pre-commit hooks (.pre-commit-config.yaml)

• Added root-level pre-commit config covering all projects
• Python: ruff (lint + format), pyright (sqlalchemy, tortoise-orm only)
• Java: Google Java formatter
• YAML: prettier
• GitHub Actions: actionlint
• Secrets: gitleaks
• Removed per-project .pre-commit-config.yaml files (sqlalchemy, tortoise-orm)

CI workflows

• Added pre-commit workflow to run pre-commit checks
• Removed redundant lint jobs from Python CI workflows (now handled by pre-commit workflow)
• Added build step to sqlalchemy and tortoise-orm CI workflows
• Added uv lock --check to all Python CI workflows to catch out-of-sync lock files

Consolidated files

• Moved LICENSE_HEADER.txt to repo root, removed per-project copies
• Moved .mise.toml to repo root, removed per-project copies
• Added pre-commit setup instructions to CONTRIBUTING.md

This PR depends on #10, #11, and #12 to make the checks pass. Once those are merged I will mark this as ready for review. Until then, the checks will fail (as they are designed to do).

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