Convert the thumbnail context menu to display in React (BL-15895)

[StephenMcConnel]

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This change is 

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 5 additional findings.

[hatton]

1. JS requests menu items from C# → receives [{id, label, enabled}, ...]
2. User clicks an item → JS sends the commandId back to C# for execution

@StephenMcConnel would it be more natural for the UI (typescript) to know the menu items it wants?

[StephenMcConnel]

I thought about it but came up with two reasons for keeping the way the AI structured things:

1. There would need to be an API call for each menu item to get its localized label.
2. There would need to be an API call for each menu item to get its enabled state, although maybe that could be computed on the client side. I haven't really looked at that.
   Making a single API call to get all of the menu items with those values already computed seemed like a reasonable choice with
   simpler setup.

@StephenMcConnel made 1 comment.
Reviewable status: 0 of 4 files reviewed, all discussions resolved.

[hatton]

Yeah, let's "go native" for all of these menus, not rely on the server to act like part of the UI. We have UI all over in typescript land that manages to localize itself one way or the other :-)

@hatton made 1 comment.
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[StephenMcConnel]

OK.

@StephenMcConnel made 1 comment.
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