Add Escape key handling for inline search in SInputDropdown

[Copilot]

Adds standard Escape key behavior to the inline search dropdown: first press clears the search query, second press closes the dropdown.

Changes:

• Added Escape key handler in handleInlineKeydown:
  • Clears inlineQuery and inlineActiveIndex when query exists
  • Closes dropdown via close() when query is empty
• Added test coverage for all Escape key scenarios

Behavior:

// User types "Opt" in search
handleInlineKeydown({ key: 'Escape' })  // Clears query, dropdown stays open
handleInlineKeydown({ key: 'Escape' })  // Closes dropdown

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