Add 'resolveImageSource' option to support cid image source for canvas editing

[liangdrime]

Summary

Fix image editing for content-model scenarios where image src uses cid: protocol by introducing a new resolveImageSource option.

This allows clients to convert cid: URLs to canvas-safe URLs (such as base64 data URLs) before edit operations run.

Background

On the Outlook for iOS/Mac, images are stored as cid: URLs.
Canvas APIs cannot draw cid: images directly, so editing features that depend on canvas regeneration fail.

Before content model, the client could override setEditingImage to convert cid: to base64 before editing.
In content model flow, relying on this approach to override some interface is not reliable.

What changed

• Added resolveImageSource?: (src: string) => string | undefined to ImageEditOptions.
• Wired resolveImageSource into ImageEditPlugin.canRegenerateImage(...).
• Updated canRegenerateImage(...) utility to recognize resolvable image sources as regeneratable.
• Updated image clone path in createImageWrapper(...) so editing uses resolved, canvas-safe src.

Example usage

new ImageEditPlugin({
    resolveImageSource: src =>
        src.startsWith('cid:') ? getBase64DataFromCid(src) : undefined,
});