feat: remove app name and logo customization feature

Users can no longer customize the app name or logo. The branding API
endpoints, permission, frontend UI, env vars (APP_NAME, MAX_LOGO_SIZE_KB),
and all related tests are removed. Includes a migration to clean up
branding data from existing databases.

apps/api/src/lib/env.ts

@@ -26,7 +26,6 @@ const envSchema = z.object({
   WORKSPACE_PATH: z.string().default("./tmp/workspace"),
   DEFAULT_THEME: z.enum(["light", "dark", "system"]).default("light"),
   DEFAULT_LOCALE: z.string().default("en"),
-  APP_NAME: z.string().default("snapotter"),
   CORS_ORIGIN: z.string().default(""),
   MAX_USERS: z.coerce.number().default(0),
   LOG_LEVEL: z.enum(["fatal", "error", "warn", "info", "debug", "trace"]).default("info"),
@@ -35,7 +34,6 @@ const envSchema = z.object({
   MAX_PIPELINE_STEPS: z.coerce.number().default(0),
   MAX_CANVAS_PIXELS: z.coerce.number().default(0),
   MAX_SVG_SIZE_MB: z.coerce.number().default(0),
-  MAX_LOGO_SIZE_KB: z.coerce.number().default(500),
   MAX_SPLIT_GRID: z.coerce.number().default(100),
   MAX_PDF_PAGES: z.coerce.number().default(0),
   SESSION_DURATION_HOURS: z.coerce.number().default(168),