Gpm::upgradeGrav() now calls generatePreflightReport() from the new
package's Install.php before proceeding. If incompatible plugins are
detected, a detailed error message is shown listing which plugins need
to be disabled.
Adds colored compatibility badges (1.7 blue, 1.8 green) to:
- Plugin list, theme list, and plugin detail views
- SCSS badge styles (.gpm-compat-17, .gpm-compat-18, .gpm-compat-api)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>