feat(cc-config): switch between Claude Code accounts, keeping the workspace

Adds a "Switch profile" button left of Backups on /settings?tool=claude-code.
A *profile* is one Anthropic account - one quota - saved under a name, so the
local `claude` CLI can be pointed at a different account without disturbing
anything else.

A switch swaps exactly two identity artifacts and nothing more: `claudeAiOauth`
inside `<CLAUDE_HOME>/.credentials.json`, and `oauthAccount` + `userID` inside
the `.claude.json` config file(s). Those files are key-merged in place, and only
where they already exist, so `projects`/`numStartups`/everything else survives.
Skills, subagents, commands, memory, plugins, marketplaces, MCP servers and
settings are never read or written here - that is what makes a switch keep the
whole workspace and change only the account. `mcpOAuth` stays put too: those are
the machine's MCP server tokens, not account identity.

Profiles are one JSON file each under `<CLAUDE_HOME>/agenthub-profiles/` (dir
0700, files 0600, atomic temp+rename) and hold live OAuth tokens, so no route
ever returns token material - `GET /profiles` answers identity metadata only.

The dashboard cannot log an account in; only `claude auth login` mints tokens.
Adding a profile is therefore always "log in from a terminal, then snapshot what
the CLI wrote". `activateProfile` re-snapshots the outgoing account first so
tokens Claude Code refreshed since its last save are not lost, and refuses
(`EUNSAVED`) to switch away from an account that was never saved - that would
discard the only copy of its credentials. A switch applies to new sessions only,
since a running session rewrites the config on exit.

Routes: GET/POST/DELETE /api/cc-config/profiles, POST /profiles/activate.

Verified: server 1420/1420 (14 new, incl. token-free responses and 0600/0700
permissions), client 459/459.

client/src/i18n/locales/en/ccConfig.json

@@ -215,6 +215,29 @@
     "scopeLabel": "Scope",
     "filterAll": "All types"
   },
+  "profiles": {
+    "title": "Claude Code profiles",
+    "openButton": "Switch profile",
+    "subtitle": "A profile is one Anthropic account - its own quota. Switching swaps only the login (credentials + account identity); skills, subagents, memory, plugins, marketplaces, MCP servers and settings all stay exactly as they are.",
+    "warning": "Close your running Claude Code sessions before switching - a live session rewrites the config on exit and would put the old account back.",
+    "activeLabel": "Logged in now",
+    "noActive": "No Claude account is logged in on this machine.",
+    "unsavedActive": "This account is not saved as a profile yet - save it below, otherwise you cannot switch away without losing its credentials.",
+    "saveLabel": "Save the current account as a profile",
+    "namePlaceholder": "profile name (e.g. work)",
+    "saveButton": "Save",
+    "saveHint": "The dashboard cannot log in for you. To add another account: run `claude auth login` in a terminal, sign in, then come back and save it under a new name.",
+    "saveSuccess": "Saved the current account as profile \"{{name}}\".",
+    "empty": "No profiles saved yet - save the account you are logged in as to get started.",
+    "activeBadge": "active",
+    "switchButton": "Switch to",
+    "switching": "Switching…",
+    "switchSuccess": "Switched to profile \"{{name}}\". Start a new Claude Code session to pick it up.",
+    "deleteButton": "Delete profile",
+    "deleteSuccess": "Deleted profile \"{{name}}\".",
+    "savedAt": "Saved {{time}}",
+    "loginHint": "Add another account by logging in from a terminal first:"
+  },
   "explain": {
     "hooks": {
       "title": "Editing hooks writes settings.json",