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.

packages/shared/src/i18n/en.ts

@@ -193,7 +193,6 @@ export const en = {
     sidebarView: "Sidebar",
     fullscreenView: "Fullscreen Grid",
     version: "Version",
-    appName: "App Name",
     uploadLimit: "File Upload Limit",
     defaultTheme: "Default Theme",
     defaultLocale: "Language",
@@ -247,14 +246,6 @@ export const en = {
       startupCleanup: "Startup Cleanup",
       startupCleanupDescription: "Clean up old temporary files when the server starts",
     },
-    branding: {
-      logo: "Custom Logo",
-      logoDescription: "Upload a custom logo for the sidebar and navbar",
-      uploadLogo: "Upload Logo",
-      removeLogo: "Remove Logo",
-      logoRequirements: "PNG, SVG, or JPEG. Max 500KB.",
-      dragDrop: "Drag and drop or click to upload",
-    },
     limitsAndResources: "Limits & Resources",
     maxFileSize: "Max File Size",
     maxBatchSize: "Max Batch Size",
@@ -269,7 +260,6 @@ export const en = {
     envOverride: "Set by environment variable",
     maxCanvasPixels: "Max Canvas Pixels",
     maxSvgSize: "Max SVG Size",
-    maxLogoSize: "Max Logo Size",
     maxSplitGrid: "Max Split Grid",
     maxPdfPages: "Max PDF Pages",
     sessionDuration: "Session Duration",

packages/shared/src/permissions.ts

@@ -10,7 +10,6 @@ export type Permission =
   | "settings:write"
   | "users:manage"
   | "teams:manage"
-  | "branding:manage"
   | "features:manage"
   | "system:health"
   | "audit:read";