fix(percy): use percy upload for clone — works with any project type

Replace manual tile-based API calls with `percy upload` CLI command.
This fixes:
- Web projects getting cloned as app type (now uses same project)
- Comparison 400 errors (CLI handles API format internally)
- Device names showing as "Screenshot [Clone]"
- Rate limiting from many sequential API calls

Two modes: `percy snapshot` for URL-named snapshots, `percy upload`
for named snapshots. Both use Percy CLI and the existing target project.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: DeRaowl