(testapp) Structure sword stuff better in the ui + warn when battles will 100% kill you.

[afti-githobo]

Description

This pull request implements requested revisions to the testapp UX:

• You have skull icons on battles you'll always lose.
• The buy/upgrade sword buttons only appear if you're currently working toward sword level 1 or 2, respectively, and are greyed out and unusable if you don't have enough of the respective currencies.

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