Add Floaty CSV support (written with AI)

[DT1000101]

Summary

• Add support for Floaty CSV exports (previously only Floaty JSON worked; CSV was misrouted through the Float Control parser and hung on the loading screen).
• Detect Float Control vs Floaty CSV by headers, and show a clear error for unrecognised CSV formats instead of spinning forever.
• Update Welcome/README copy and add fixture + unit tests for routing and Floaty CSV mapping.

Test plan

• Load a Floaty .csv export — ride opens (no infinite “Parsing your ride…”)
• Load a Floaty .json export — still works as before
• Load a Float Control CSV / ZIP — still works
• Load a VESC Tool semicolon CSV — still works
• Load a junk CSV with unknown headers — alert + return to file picker
• npm run checks

Made with Cursor

[acheronfail]

Thanks for this change! I've made a couple adjustments to it, but otherwise it seems good.

I'll merge it in and it'll be out in the next release.