Reduce Appshots white flash intensity, especially in dark mode

What issue are you seeing?

When using Appshots in the Codex desktop app, the screen flashes bright white to indicate that a screenshot is being taken.

The effect is a nice confirmation the first time, but it is uncomfortable and discourages repeated use. In dark mode especially, the full white flash feels like a flashbang.

Expected behavior

Appshots should still provide a clear capture acknowledgment, but the visual effect should be less disruptive.

Possible improvements:

• Use a darker or theme-aware flash in dark mode.
• Reduce the flash opacity/duration.
• Prefer a subtle bounded/window-level indication instead of a full bright-screen flash.
• Consider making the capture flash configurable or respecting reduced-motion / accessibility preferences.

Actual behavior

Taking an Appshot produces a bright white flash, which is jarring during repeated captures and particularly harsh in dark mode.

Why this matters

Appshots are useful enough to use repeatedly while working, but the current flash makes each capture unpleasant. A less intense or theme-aware confirmation would preserve the affordance without making the feature feel punishing to use.