Split view, personal modes, budget warnings, server move script

- Up to three chats side by side (#/s/a+b+c), "Open beside" in the sidebar menu
- File manager tabs of a chat stored per user on the server (/sessions/{id}/tabs)
- Personal modes for every user (Settings → My modes, /account/modes)
- Budget meters (total, provider, images, opencode Go windows) with push warnings
  for admins at the warning share and 100 %, shown in the status overlay
- scripts/move-server.sh: move to another Docker host with bind mounts (Unraid);
  scripts/smoke-test.sh

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/i18n/en.ts

@@ -214,6 +214,7 @@ export const en = {
   "sidebar.week": "Last 7 days",
   "sidebar.older": "Older",
   "status.title": "Status",
+  "status.budgets": "Budgets",
   "status.server": "Server",
   "status.models": "Models",
   "status.mcp": "MCP",
@@ -453,6 +454,13 @@ export const en = {
   "shareIn.newChat": "Start a new chat",
   "shareIn.appendTo": "or add to a recent session",
   "common.back": "Back",
+  "settings.tab.modes": "My modes",
+  "modes.intro": "Your own modes: a prompt, a kind (coding or conversation), tools and an optional model. They appear in New session and in the mode selector of your chats – only for you.",
+  "modes.none": "You have no modes of your own yet.",
+  "modes.exists": "A mode named {name} already exists.",
+  "modes.promptPlaceholder": "e.g. You are a patient German teacher. Correct my sentences and explain briefly why.",
+  "agents.styleChatShort": "conversation",
+  "agents.styleCodingShort": "coding",
   "settings.tab.templates": "Templates",
   "templates.title": "Prompt templates",
   "templates.filter": "Search templates…",
@@ -485,6 +493,8 @@ export const en = {
   "sidebar.organise": "Organise session",
   "sidebar.pin": "Pin to top",
   "sidebar.unpin": "Unpin",
+  "sidebar.openBeside": "Open beside",
+  "chat.closePane": "Close this column",
   "sidebar.moveTo": "Move to folder…",
   "sidebar.removeFromFolder": "Remove from folder",
   "sidebar.archiveOne": "Archive",
@@ -845,6 +855,7 @@ export const en = {
   "agents.modePrimary": "mode",
   "agents.modeSubagent": "subagent",
   "agents.source.builtin": "built-in",
+  "agents.source.personal": "personal",
   "agents.source.config": "config",
   "agents.source.file": "file",
   "agents.model": "Model",