Add ability to add non-"Direct Beam" PV-labeled runs to the Direct Beam table

[darshdinger]

Description of work:

Allow users to add any run to the Direct Beam table even if the EPICS PV data_type is not set to indicate a direct beam (data_type != 1). This enables calibration and other runs started with EPICS "Start RUN" (which may not set the Direct Beam PV-tag) to be used as normalization runs.

Key changes:

• DataManager.add_active_to_direct_beam_list() now accepts any run and returns an integer status:
  • 2 — added and is a true direct beam (data_type == 1)
  • 1 — added but not labeled as a direct beam (data_type != 1); logs a warning
  • 0 — not added (already present)
• MainHandler.add_direct_beam() updated to show a non-blocking warning message when a non-direct-beam run is added (keeps blocking error for duplicates).
• Kept is_direct_beam metadata unchanged to preserve original metadata integrity and avoid altering run semantics.
• PlotManager.plot_reflectivity_or_intensity() updated to check if active data is in the direct beam list (in addition to checking is_direct_beam attribute) to correctly display "Intensity" plots for non-direct-beam runs added to the direct beam table.
• Note: Users can intentionally add the same run to both the Direct Beam table and the Data/Reduction table. This is a supported use case for comparing different ROIs (e.g., portion of beam that misses the sample vs. reflected beam on the same detector). When a run exists in the direct beam list, it will display as "Intensity" regardless of also being in the reduction table.
• Added comprehensive tests to cover behavior and backward compatibility:
  • Unit tests using real data (marked @pytest.mark.datarepo)
  • Mock-based unit tests that don't need data files
  • UI integration tests that confirm warnings, duplicate handling, normalization behavior, and plot display

Check all that apply:

• updated documentation and checked that it looks correct in the pull request preview
• Source added/refactored
• Added unit tests
• Added integration tests

References:

• Links to IBM EWM items: EWM 11847
• Links to related issues or pull requests: (none)

⚠️ Manual test for the reviewer

(Quick steps to exercise the feature locally; CI may need the data repo for full integration tests.)

1. Set up the environment:
   • Ensure dependencies installed (pixi env used in this repo).
2. Run non-datarepo unit tests (fast smoke test):

   pixi run pytest test/unit/quicknxs/interfaces/test_data_manager_direct_beam_mock.py -v

3. Run UI tests or datarepo tests only if you have the SNS data available:

   # run UI tests (requires data Server fixture / datarepo)
   pixi run pytest test/ui/test_add_non_direct_beam.py -v
   
   # Or run the specific integration tests marked datarepo:
   pixi run pytest -m datarepo test/unit/quicknxs/interfaces/test_data_manager_direct_beam.py -v

4. Manual interactive check:
   • Start the GUI (if you normally launch QuickNXS).
   • Load a scattering run (a run whose data_type PV is not 1).
   • Use "Add Direct Beam" (Ctrl+W or Reduction → Add Direct Beam) — confirm the run is added to the Direct Beam table and a non-blocking warning is shown in the status/message area.
   • Select the added run from the Direct Beam table by clicking its radio button — confirm the lower-right plot displays "Intensity" (not "Reflectivity").
   • Try to add the same run again — confirm a blocking error message appears and no duplicate is added.
   • Load another scattering run, add it to the Data table, set its direct_beam parameter to the previously added run, and run reflectivity calculation to confirm normalization works.
   • Optional: Add the same run to both Direct Beam and Data tables — confirm that selecting it from either table shows "Intensity" plot (this is expected behavior for ROI comparison workflows).

(instructions to set up the environment)

Check list for the reviewer

• best software practices
  • clearly named variables (better to be verbose in variable names)
  • code comments explaining the intent of code blocks
• All the tests are passing
• The documentation is up to date and looks correct in the pull request preview
• code comments added when explaining intent

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.76543% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 65.57%. Comparing base (ad9201b) to head (7973419).
⚠️ Report is 9 commits behind head on next.

Files with missing lines	Patch %	Lines
...quicknxs/interfaces/event_handlers/main_handler.py	98.48%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             next     #229      +/-   ##
==========================================
- Coverage   65.72%   65.57%   -0.15%     
==========================================
  Files          37       37              
  Lines        6909     6914       +5     
==========================================
- Hits         4541     4534       -7     
- Misses       2368     2380      +12     

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