Move build-time ditto.json injection from a Vite define global to
import.meta.env.DITTO_CONFIG (a JSON string parsed and validated at
runtime via DittoConfigSchema). Remove the global type declaration
from vite-env.d.ts.
Drop ThemeSchemaCompat and its legacy "black"/"pink" migration code
from AppProvider and NostrSync — invalid theme values now simply fail
Zod validation.
Fix a latent bug where a partial feedSettings from ditto.json would
replace the full hardcoded defaults; defaultConfig now deep-merges
feedSettings.
Alex Gleason