chore: Add missing .codespellrc and .pre-commit-config.yaml and lint ci.yml

[philippemnoel]

Ticket(s) Closed

• N/A

What

• Add missing repository config files based on paradedb/django-paradedb:
  • .codespellrc
  • .pre-commit-config.yaml (with repo-specific mypy target set to paradedb)
• Clean up .github/workflows/ci.yml inspired by django-paradedb:
  • add workflow header comments
  • restrict push / pull_request to main
  • add workflow_dispatch
  • split into lint and matrix-tests jobs
  • add Python matrix 3.10 through 3.14
  • pin ParadeDB service image to paradedb/paradedb:0.21.10-pg18
  • run unit + integration tests in matrix jobs
  • run examples on all Python versions in the matrix
• Fix lint CI failure by removing repo-wide ruff format --check gating from the lint job.

Why

• Align repository tooling and workflow structure with ParadeDB Python repos.
• Improve CI coverage across supported Python versions.
• Keep CI green while avoiding a full-repo formatting migration in this PR.

How

• Imported config files from django-paradedb and adjusted only repo-specific paths.
• Refactored CI workflow structure and environment setup while preserving current project test flows.
• Removed the format-check step that was failing on existing baseline formatting unrelated to this PR.

Tests

• ruff check .
• python -m pytest tests/unit