Add opt-in auction search dialog

[LIUZAZA007]

Adds an optional search dialog with a prefilled query and separate Search, Clear and Cancel buttons. dialog.enabled defaults to false, preserving existing chat search, right-click reset and inventory lore. Dialog text is configurable in six bundled locales.

Callbacks validate the viewer and input length, reject stale sessions, and run auction operations on the player scheduler. The change also removes stale menu registrations on unload/reload and repairs earlier search templates missing the required action section.

Validation:

• Gradle build passed with Java 21 and an English/US JVM locale.
• Regression harnesses passed for template upgrades, idempotence and disabled-plugin click handling.
• YAML and packaged resources checked; git diff --check passed.
• Gradle test tasks report NO-SOURCE. Live server and client compatibility testing has not been performed.