[feat] Escape database name completions

[scottnemes]

Description

• Escape database name completions.
• Update completion test setup to extend database names.
• Add test for database name completions.

Before:

After:

Checklist

• I've added this contribution to the changelog.md.
• I've added my name to the AUTHORS file (or it's already there).
• I ran uv run ruff check && uv run ruff format && uv run mypy --install-types . to lint and format the code.

[rolandwalker]

Lovely