Questdb archiver connector

[chrisbchin11-ui]

Quest DB Connector:

• New archiver connector that retrieves historical PV data from a QuestDB instance and exposes it through OSPREY's existing 'ArchiverConnector' interface
• Implements the abstract base case in base.py: 'connect(config)', 'disconnect()', 'getdata(pv_list, start_date, end_date, precision_ms=1000, timeout=None)', 'get_metadata(pv_name)' 'check_availability(pv_names)', '
• test_questdb_archiver_connector.py:

1. Unit tests mocks the 'asyncpg' client to run with no live database
2. Uses an integration test gated by '@pytest.mark.integration'
3. Covers the edge cases (empty 'pv_list', a PV with no data in range, an empty time range, not-connect error path)

• Gracefully handles missing-dependency case if 'asyncpg' is not installed - raises an 'ImportError' with an actionable install message
• Honors 'precision_ms' by downsampling server-side with QuestDB's 'SAMPLE BY'
• 'check_availability' is a single batched query rather than one per PV
• Uses a connection pool with a bounded timeout, and 'timeout' cancels a slow query

[chrisbchin11-ui]

Dockerfile E2E check is failing but is unrelated to this pull request and looks pre-existing.

[chrisbchin11-ui]

Updated 6/22/26:

1. More robust queries using parameters instead of f-strings
2. Datetimes are time-zone aware (converts to UTC)
3. Error handling double checked: start/end times must be actual datetimes, connect() catches more specific errors besides just connection errors, get_metadata and check_availability raise errors if a query fails