Add source-quality columns and code for h5 migration

[jeanconn]

Description

• add new source-quality fields to the database and source-detection pipeline:
  psfratio, concentration_ratio, grating_arm, brightest, and
  peak_offset
• add a database/h5 migration for existing tables
• expand DB, observation, and source-detection coverage for the new columns

We haven't really decided what final set of source quality columns will be used, but this adds a few that could be useful.

Interface Impacts

• astromon_xray_src gains the source-quality columns psfratio,
  concentration_ratio, grating_arm, brightest, and peak_offset
• observation outputs and persisted source rows now expose those fields
• downstream code that reads astromon tables can start depending on the new columns

Testing

• adds unit tests for the DB migration, the new xray-source columns in persisted
  tables, and the observation/source-detection plumbing that fills them

Migration

• no standalone action at this PR boundary
• when the full stack is approved and merged, run
  astromon/scripts/migrate_db.py before deploying code that expects the new
  columns

Unit tests

• Mac

$ python -m pytest astromon/ -v
============================= test session starts ==============================
platform darwin -- Python 3.13.11, pytest-9.0.2, pluggy-1.6.0
collected 105 items
astromon/tests/test_cross_match.py ..................... (21 passed)
astromon/tests/test_db.py .................. (18 passed)
astromon/tests/test_observation.py ................. (17 passed)
astromon/tests/test_source_detection.py .......... (10 passed)
astromon/tests/test_stored_result.py ................ (16 passed)
astromon/tests/test_task.py ....sssssssssssssss.s.. (7 passed, 16 skipped — skips require HEAD/network access)
======================= 89 passed, 16 skipped in 27.40s ========================

Independent check of unit tests by [REVIEWER NAME]

• [PLATFORM]:

Functional tests

No functional testing.