docs(dashboard): document machine-level multi-profile management

- web-dashboard.md: 'Managing multiple profiles' section (switcher, URL
  deep-links, unified launch, --isolated, scoped Chat, what stays
  per-profile) + --isolated in the options table
- profiles.md: 'From the dashboard' subsection + set-as-active vs
  switcher clarification
- cli-commands.md: --isolated flag + profile-alias launch example

website/docs/user-guide/profiles.md

@@ -199,6 +199,20 @@ If you want this profile to work in a specific project by default, also set its
 coder config set terminal.cwd /absolute/path/to/project
 ```
 
+### From the dashboard
+
+The [web dashboard](features/web-dashboard.md#managing-multiple-profiles)
+is a machine-level surface that can manage **any** profile's config, API
+keys, skills, MCPs, and model via the profile switcher in its sidebar — no
+per-profile dashboard needed. `coder dashboard` routes to the machine
+dashboard with the `coder` profile preselected. The dashboard's Chat tab
+also follows the switcher, spawning a conversation under the selected
+profile's home.
+
+Note: "Set as active" on the dashboard's Profiles page is the sticky
+default for **future CLI/gateway runs** (same as `hermes profile use`) —
+to edit a profile from the dashboard, use the switcher instead.
+
 ## Updating
 
 `hermes update` pulls code once (shared) and syncs new bundled skills to **all** profiles automatically: