#14 Restore localized `Menu.Search` label and placeholder; remove unused search resource keys

[Anonymous]

Originally created by: Avazbek22

Motivation

• Restore translation support for the Search UI so the menu label and the search textbox placeholder are localized via Menu.Search instead of a hard-coded string.
• Remove unused per-button search localization keys from resource files while preserving the icon-only search controls and their glyphs.
• Ensure the cue-banner placeholder is reapplied when language changes and on startup.

Description

• Replaced hard-coded search placeholder with a localized value by using SendMessage (EM_SETCUEBANNER) in ApplySearchPlaceholder() and calling it from the constructor and ApplyLocalization(); the placeholder now comes from _localization["Menu.Search"].
• Restored the miSearch menu text to use _localization["Menu.Search"] and cleared per-button tooltips while keeping icon-only search buttons (btnSearchNext, btnSearchPrev, btnSearchClose) visible and setting their glyphs/text in ApplyLocalization() and designer ordering changes (removed lblSearch and adjusted menu items).
• Added a DllImport declaration for SendMessage and the EmSetCueBanner constant in Form1.cs.
• Added Menu.Search key across localization JSON files and removed unused keys Menu.Search.Label, Menu.Search.Next, Menu.Search.Previous, and Menu.Search.Close from all language files.
• Continued previously-introduced live options behavior and ignore-selection handling: added ScanOptionsUseCase.GetExtensionsForRootFolders, PopulateExtensionsForRootSelection, PopulateIgnoreOptionsForRootSelection, UpdateLiveOptionsFromRootSelection, and an _ignoreSelectionCache to preserve ignore selections when lists are rebuilt.

Testing

• No automated tests were executed for these changes.

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Codex Task

[Anonymous]

Ticket changed by: Avazbek22

• status: open --> closed