Fixed the version using hatch-vcs.

Summary:

• hatch-vcs automatically detects versions from git tags (e.g., v2.0.3-beta1 → 2.0.3b1)
• When you push a tag like v2.0.3-beta1, the workflow will build packages with the correct version
• No manual version updates needed - just create and push git tags
• The version is baked into the package metadata at build time
• The __VERSION__ variable imports from the package metadata at runtime

Tag Format:

hatch-vcs follows PEP 440 conventions:

• v2.0.3 → 2.0.3
• v2.0.3-beta1 → 2.0.3b1
• v2.0.3-rc1 → 2.0.3rc1
• v2.0.3-alpha1 → 2.0.3a1

Finally marked the last remaining task in this PR as completed 🎉

Replaced the old Docker CI setup (Linux-only) with PSFirebird, enabling a unified workflow that runs on both Ubuntu and Windows across Firebird 3, 4 and 5.

Main change: CI rewrite (ci.yml)

• PSFirebird v1.2.2 is installed in each job to manage Firebird lifecycle (download, configure, start, stop).
• SYSDBA initialization: archive-extracted Firebird ships with an empty security database. The workflow creates SYSDBA via an embedded isql connection before starting the TCP server.
• ISC_USER / ISC_PASSWORD are set as job-level env vars so the driver test suite picks them up automatically.
• firebird.log seeding: the Service API get_log() tests assert the log is non-empty. An archive-extracted Firebird never writes startup messages to this file, so we seed it before the server starts.
• Client library path: FirebirdEnvironment.GetClientLibraryPath() is used to pass the correct library path to the test suite on both platforms (no more OS-conditional path guessing).

Minor bugs fixed

These were uncovered while getting the test matrix fully green and are small enough not to warrant their own issues:

1. conftest.py — Path → str conversion for fb_client_library (tests/conftest.py): The driver_config.fb_client_library option is a StringOption and rejects Path objects. The fix is a one-character change (wrap with str()).

2. _connect_helper — missing / separator for Windows paths in protocol URLs (src/firebird/driver/core.py): When building inet:// URLs with a host, Windows drive-letter paths were concatenated directly onto the host string, producing malformed URLs like inet://localhost:3050D:\path. Added the / separator so the result is inet://localhost:3050/D:\path, which Firebird parses correctly.

3. test_connect_config — spurious utf8filename = true (tests/test_connection.py): The database config used in this test included utf8filename = true. That option causes the Firebird engine to interpret the filename as UTF-8 bytes, which breaks attachment on Windows with drive-letter paths, producing "unavailable database". Removed the option since test_connect_config is testing config-based connection routing, not UTF-8 filename encoding.

4. test_connect_helper — expected DSN values updated (tests/test_connection.py): The unit-test assertions for _connect_helper with Windows paths and a host in protocol-URL mode were updated to match the corrected (now correct) URL format.

Rebased onto latest master.