docs: the swarm UI page shrinks to an overview

The page-by-page and control-by-control description of the swarm UI moves to
4-implementation/web-ui/swarm-ui.md, with the quick-links wiring. The handbook
page keeps the route table, how to reach the UI, who may and what the browser
keeps. Links to the moved sections point at the new page.

docs/2-handbook/external-accounts/forgejo.md

@@ -14,7 +14,7 @@ Two labels can name two forges.
 In the swarm UI, open an agent, choose **link account**, then **forge
 account**. Fill in a label, the forge's URL and an access token. The form shows
 the controller's answer if it refuses the input, and the linked account appears
-in the agent's list of [linked accounts](../swarm/ui.md#linking-external-accounts)
+in the agent's list of [linked accounts](../../4-implementation/web-ui/swarm-ui.md#linking-external-accounts)
 as kind **forge**.
 
 - `label` is lowercase letters, digits and hyphens. It names the account in the

docs/2-handbook/external-accounts/github.md

@@ -36,7 +36,7 @@ to `<state>/github-token` at runtime (see [Provisioning](#provisioning)).
 
 ## Provisioning
 
-The PAT is operator-supplied. In the [swarm UI](../swarm/ui.md#linking-external-accounts),
+The PAT is operator-supplied. In the [swarm UI](../../4-implementation/web-ui/swarm-ui.md#linking-external-accounts),
 open the agent on `/agents`, choose **link github account** and paste the PAT
 (`PUT /api/hives/{hive}/agents/{agent}/github-account`). swarm-controller
 stores it at `swarm/agents/<agent>/github-token` in the swarm secret store;

docs/2-handbook/external-accounts/gitlab.md

@@ -15,7 +15,7 @@ In the swarm UI, open an agent, choose **link account**, then **gitlab
 account**. Fill in a label, the instance URL (it starts as `https://gitlab.com`)
 and the token. The form shows the recommended scopes and the controller's
 answer if it refuses the input. The linked account appears in the agent's list
-of [linked accounts](../swarm/ui.md#linking-external-accounts) with a delete
+of [linked accounts](../../4-implementation/web-ui/swarm-ui.md#linking-external-accounts) with a delete
 action. The UI calls the controller's API, which you can also call directly:
 
 ```text

docs/2-handbook/external-accounts/matrix.md

@@ -24,7 +24,7 @@ account**. You can give the account in two ways:
   encrypted rooms. Prefer the password login.
 
 The linked account appears in the agent's list of
-[linked accounts](../swarm/ui.md#linking-external-accounts) as kind
+[linked accounts](../../4-implementation/web-ui/swarm-ui.md#linking-external-accounts) as kind
 **matrix**. The controller refuses a name that already holds an account; delete it and link
 again to replace it. Linking also allows the homeserver's host in the agent's outgoing internet
 access, and deleting the account removes it again.

docs/2-handbook/hives/README.md

@@ -75,7 +75,7 @@ VictoriaLogs; read them in Grafana's **Explore**, as
 
 **Set up a schedule.** Scheduled prompts are swarm-level: set them with
 `swarmctl schedule` ([`swarm/schedules.md`](../swarm/schedules.md)) or in the
-schedules card on the swarm UI's messages tab ([`swarm/ui.md`](../swarm/ui.md)).
+schedules card on the swarm UI's messages tab ([`swarm-ui.md`](../../4-implementation/web-ui/swarm-ui.md)).
 
 ## More depth