Add options response seams and bump version to 0.2.0

[ulsyemr]

Why

fetchOptions does more than fetch: it sequences requests, drops stale responses, and does the post-render bookkeeping. A host app whose options endpoint returns something other than a Turbo Stream currently has no way to change only the response handling — it has to reimplement the whole method and inherit the drift that comes with a copy.

What

Two extension points, both with today's behaviour as their default:

readOptionsResponse(response)   // => response.text()
renderOptionsResponse(payload)  // => Turbo.renderStreamMessage(payload)

Overriding them keeps the request sequencing, the stale response guard, aria-busy, renderOptionsState, and single-option auto-selection in the base controller.

And a third event, alongside change and advanced-select:change:

advanced-select:options-loaded  →  detail: { name, value, count }

It fires after every successful remote load — eager dependent loads included — once the options are in the DOM and any auto-selection has been applied. count is the number of selectable options, which is enough to react to an empty or single-option result without reading the DOM.