fix: prevent freeze on double right-click in directory background

[lidaixingchen]

Problem

When performing two consecutive right-clicks on the directory background area, the file explorer freezes.

Root Cause

Three interacting issues identified through debug.log analysis:

1. Single-threaded renderer_thread deadlock: The second track_popup_menu call gets queued behind the first one's event loop, causing the main thread to hang in nested wait_with_msgloop().
2. Race condition on menu_callbacks_js: The file watcher thread clears and repopulates menu_callbacks_js without synchronization, while the renderer thread iterates over it concurrently.
3. Excessive script reloading: Multiple file changes trigger cascading reloads without debouncing, causing init_known_strings to block for 200-700ms each time.

Fixes

• Add re-entrancy protection to track_popup_menu: when a menu is already showing, close it first and wait for completion before creating a new one.
• Add std::shared_mutex for menu_callbacks_js: write lock for clear/add/remove operations, read lock for iteration.
• Add 500ms debounce delay for script reloading to batch file changes.

Changed Files

• src/shell/contextmenu/hooks.cc - re-entrancy protection
• src/shell/contextmenu/menu_render.cc - shared_lock read protection
• src/shell/script/binding_types.hpp - declare menu_callbacks_js_mutex
• src/shell/script/binding_types.cc - define mutex, add write lock
• src/shell/script/script.cc - write lock protection and debounce

[Copilot]

Pull request overview

Fixes a file-explorer freeze triggered by consecutive right-clicks on the directory background by addressing re-entrancy in context menu display, synchronizing JS menu listener access, and debouncing script reloads.

Changes:

• Add re-entrancy handling in track_popup_menu to close an existing menu before showing a new one.
• Protect menu_callbacks_js with a std::shared_mutex (writers in bindings/reload; readers in menu rendering).
• Debounce JS script reloads to batch rapid filesystem change events.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/shell/contextmenu/hooks.cc	Adds re-entrancy detection/close-and-wait logic around track_popup_menu.
src/shell/contextmenu/menu_render.cc	Wraps iteration of JS menu listeners with a shared lock.
src/shell/script/binding_types.hpp	Declares a global menu_callbacks_js_mutex for synchronizing listener access.
src/shell/script/binding_types.cc	Defines the mutex and adds write-locking for add/remove listener operations.
src/shell/script/script.cc	Adds write-locking for clearing listeners during reload and introduces reload debouncing.

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