Fix strategy switch config sync conflicts

[Pigbibi]

变更

• 修复策略切换页现金/融资初始冲突：账号配置的 cash_only_execution_mode 优先参与同步，渲染前执行互斥纠偏，避免融资+预留现金比例同时锁死。
• 去掉现金/融资两个主选择器的互相禁用，改为选择后自动 reconcile，用户可从冲突态恢复。
• 修复 option_overlay_mode 账号配置未被前端同步读取的问题。
• 修复 Worker 只读到 CASH_ONLY_EXECUTION 变量时丢失 currentStrategies 条目的问题。
• 移除各平台 fallback 默认账号里的 0.03/150 预留现金值，避免“未读取到真实当前配置”时误显示为当前预留现金策略。

验证

• node tests/test_cash_financing.js
• node tests/strategy_switch_worker_validation.mjs
• python3 python/scripts/build_config.py --check
• node --check page_asset.js / strategy_profiles_asset.js / worker.js / app.js
• python3 -m unittest discover -s python/tests
• git diff --check

[github-actions]

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Gate saved option overlays by strategy support

When an account has option_overlay_mode: "enabled" saved and the user switches that account to a strategy without option overlay defaults, such as ibit_smart_dca, this early return keeps form.optionOverlayMode as enabled. The render path then disables the option-overlay select for unsupported strategies, while hasValidOptionOverlayPolicy() rejects enabled on unsupported strategies, leaving the dispatch button disabled with no way for the user to clear the saved mode from the UI.

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[chatgpt-codex-connector]

Clear stale saved reserve before restoring it

After a reserve policy is saved in _prevReserve by toggling allow-margin on, that field is not cleared when the user later changes accounts or explicitly changes the reserve policy to none. In those flows this restore path can resurrect the previous account's or previously-cleared reserve settings the next time allow-margin is toggled off, causing a dispatch with an unexpected reserve-cash override.

Useful? React with 👍 / 👎.