Fix image insertion parameter order in HomeScreen

[editinghero]

Fixes an issue in HomeScreen where the URL and alt text parameters were swapped when inserting an image via ImageUrlDialog, causing incorrect markdown bracket generation.

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PR created automatically by Jules for task 2805423972481157637 started by @editinghero

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[editinghero]

Merged locally into main in commit aa1eaae with additional security hardening and biometric cleanup.