feat: record OpenWindow and ResizeWindow events

[allansson]

Description

Adds two new browser recording events:

• open-window: emitted once when the recording starts, includes initial window dimensions.
• resize-window: emitted after a resize interaction settles (debounced), includes final window dimensions.

Codegen treats these as no-ops for now.

Demo:

demo_open_and_resize_window.mp4

Recorder browser events list showing open-window and resize-window

How to Test

• Start the app in recorder mode, begin recording.
• Confirm an open-window event appears with the current size.
• Resize the browser window and stop resizing.
• Confirm exactly one resize-window event is recorded with the final size.

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have commented on my code, particularly in hard-to-understand areas.

Related PR(s)/Issue(s)

N/A

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