[muaviz]

Fixes an issue where components connected downstream of another component remained disabled/read-only even after the upstream component or connection line was deleted following a
simulation.

With this change, component editability dynamically reflects the live graph connection state on the canvas:

• If a component is connected to the output of an upstream component (e.g. an intermediate or product stream), its property window inputs are disabled/read-only.
• If a component is not connected to any upstream component (a feed stream or isolated component), its property window is immediately re-enabled/editable, even if a simulation was
  previously executed.
• If a connection is restored or re-created, the downstream component becomes read-only again.

---

Key Changes

1. Centralized Editability Synchronization (Container.update_components_editability):

   • Added update_components_editability() to evaluate every component's incoming connection state on the canvas.
   • For MaterialStream, calls disableInputDataTab when fed by an upstream unit, and enableInputDataTab when it has no upstream feed.
   • For other components, ensures isolated or un-fed components are editable (set_read_only(False)).

2. Triggering on Canvas State Changes:

   • Node and Line Deletions (Container.delete): Triggers update_components_editability() immediately after removing deleted nodes and lines from the scene.
   • Socket Connections (Graphics.mouseReleaseEvent): Recalculates editability as soon as an inlet or outlet line is connected.
   • Undo / Redo & Canvas Reload (Graphics.load_canvas_from_snapshot): Recalculates editability after rebuilding components and lines.
   • Dynamic Socket Port Resizing (Graphics.update_input_ports, update_output_ports): Recalculates editability when ports are modified.
   • Simulation Results (Container._populate_results): Updates editability preserving connection-based restrictions across all components without permanently locking
     disconnected units.

3. Stream State Controls (Streams.enableInputDataTab & Streams.disableInputDataTab):

   • Implemented enableInputDataTab() to safely re-enable the flash mode combo box, P/T/flow line edits, composition mole fractions (x_pclist), thermodynamic package dropdown,
     and Submit button.
   • Hardened disableInputDataTab() with safe attribute checks.

4. Automated Unit Tests (TestDynamicComponentEditability in tests/test_container.py):

   • Added unit tests covering:
     • Component becoming read-only when connected downstream.
     • Component becoming editable when the connection line is deleted.
     • Component becoming editable when the upstream component is deleted.
     • Full post-simulation lifecycle (MS1, MS2 -> Mixer -> MS3 simulated, Mixer deleted, MS3 verified editable immediately).
     • Reconnecting and disconnecting cycles.
     • Isolated component editability.