Fix selection clearing round-trip in multi-component state sync

[t0mdavid-m]

Summary

Fixes a bug where clearing a selection (e.g., deselecting an amino acid or switching proteoforms) in one FLASHViewer component would not propagate to other components. The issue occurred because cleared fields were being dropped from the state payload entirely, preventing the merge-only StateTracker from learning about the deselection.

Changes

• src/render/render.py: Modified render_component() to handle cleared selections properly:

  • Cleared selections now arrive as None instead of being dropped from the payload
  • Added filtering logic to strip None-valued keys before passing state to update_data() and filter_data(), preserving the "key not in selection_store" convention used by update/filter logic
  • Full state (including None values) is still echoed back to the frontend so all component instances can clear their local fields
  • Fixed trailing whitespace

• tests/test_selection_clear.py: Added comprehensive test suite documenting the fix:

  • test_selecting_a_value_round_trips() — verifies normal selection flow
  • test_clearing_a_selection_round_trips_as_none() — validates the two invariants: (1) cleared fields echo back as None, (2) None values are stripped for data computation
  • test_dropped_key_keeps_stale_value_regression() — documents the original bug and confirms the fix prevents it

• js-component/dist/: Updated built assets (index-3e659711.js, index.html) to reflect frontend changes

Implementation Details

The fix relies on two key invariants:

1. When a selection is cleared, the frontend sends None (App.vue maps undefined → null for JSON serialization), and this None is echoed back in the state so every component instance can clear the field locally
2. The active_state dict (with None values filtered out) is passed to data computation functions, maintaining backward compatibility with existing update/filter logic that uses the "key not in selection_store" convention

This approach allows the StateTracker to properly track state changes via round-tripping while preserving the existing data-computation semantics.

https://claude.ai/code/session_01TWkpASnLwnhMAQRxuYFpNs

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: b64b9815-dfa6-4751-86de-866508fa5c4d

📥 Commits

Reviewing files that changed from the base of the PR and between d0028fa and c684255.

⛔ Files ignored due to path filters (2)

• js-component/dist/assets/index-3e659711.js is excluded by !**/dist/**
• js-component/dist/index.html is excluded by !**/dist/**

📒 Files selected for processing (2)

• src/render/render.py
• tests/test_selection_clear.py

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/peaceful-keller-CGKm2

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