Promote the Streamlit Dashboard from Discovery

[tatopenn-cell]

Brings the Dashboard tested in Dense-Evolution-Discovery (PRs #240, #242) into tools/dashboard:

• English interface
• Drag-and-drop circuit editor (gate matrix on hover, undo/redo, circuit kept in the URL), works offline
• Fixes: QASM Load buttons, Qiskit-ordered results display, QEC default stabilizers and Pauli error validation, VQE warning only when needed
• Installers download the new files (sota_views.py, engine_explorer.py, circuit_editor.py); Windows uninstaller stops running processes before removing the folder
• dashboard-installers workflow: install, launch, AppTest run and uninstall on Windows, macOS and Linux

The app only uses public dense_evolution and dashboard_core APIs already in 8.3.0; the engine is unchanged.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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