Add held-modifiers context across an action group

[JE-Chen]

Summary

Round-11, automation-core. hotkey releases its keys immediately — no way to hold ctrl/shift down across several independent actions (shift-click range select, ctrl-click multi-select) with a guaranteed release.

Layers

• Headless core: je_auto_control/utils/modifier_state/modifier_state.py — hold_modifiers (context manager: press on enter, release reversed on exit in a finally), plan_with_modifiers (pure op-plan). Injectable sink; no PySide6.
• Facade: both re-exported + __all__.
• Executor: AC_with_modifiers (runs a nested JSON action list while modifiers held, release-safe — mirrors the bulkhead nested-action pattern).
• MCP: ac_with_modifiers (SIDE_EFFECT_ONLY).
• Script Builder: one CommandSpec under Keyboard.

Tests / docs

• test/unit_test/headless/test_modifier_state_batch.py — 7 headless tests (plan reversed-release, context press/body/release, release-even-on-exception, yields modifier list + wiring + facade). No real input.
• EN/Zh feature docs v123_features_doc.rst + toctrees; 3 WHATS_NEW entries.

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[codacy-production]

Not up to standards ⛔

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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