v0.7.1 — Fix: default image rules to whole-screen scanning

Fix: image rules now default to whole-screen scanning

Follow-up to v0.7.0's instant-trigger rules. A screen-cropped image trigger defaulted to matching only inside the exact box it was captured from — if the target ever moved (a button shifts, a window resizes, the UI relayouts), the rule would silently stop detecting it entirely. That defeats the point of an image-based trigger, which should find its target wherever it shows up.

Scan the whole screen is now checked by default when capturing an image from the screen (it was already forced-on for uploaded image files). You can still uncheck it for a smaller, faster scan region with fewer false positives if you specifically want the target locked to one spot.

No backend or schema changes — this is a GUI-only default flip. Existing saved rules are unaffected either way.

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修正：圖片規則現在預設全螢幕掃描

接續 v0.7.0 的即時觸發規則。從螢幕框選出來的圖片觸發，原本預設只在當初框選的那個確切區域裡比對 —— 如果目標日後移動了位置（按鈕位移、視窗改變大小、介面重新排版），規則會直接、無聲無息地再也偵測不到。這違背了圖片觸發的本意：應該要能在目標出現的任何地方找到它。

從螢幕框選圖片時，Scan the whole screen 現在預設打勾（上傳圖片檔案的情況本來就已經強制全螢幕）。如果你確實想把目標鎖定在同一個位置、換取更快的掃描速度與更少的誤判，仍然可以自己取消勾選。

沒有任何後端或資料格式變動 —— 這純粹是 GUI 端的預設值調整，不影響任何已經存好的規則。