docs: the hive dashboard and agent page shrink to overviews

The hive dashboard and the per-agent page lose their control-by-control UI
description and endpoint tables from the handbook. The full text moves to
4-implementation/web-ui/dashboard.md and agent-page.md, and the handbook pages
keep what an operator needs to find and use them. Code comments that named the
old sections point at the new pages.

docs/4-implementation/agent-state/config-changes.md

@@ -205,7 +205,7 @@ each `git` call inline, never writing it into a repo's config, so
 no stored token sits in a repo an agent might one day read.
 
 The dashboard deep-links into this org — a `config repo` link
-per container row. See `docs/2-handbook/hives/dashboard.md`.
+per container row. See `docs/4-implementation/web-ui/dashboard.md`.
 
 ### Submitting agent's view of config repos
 

docs/4-implementation/agent-state/persistence.md

@@ -247,7 +247,7 @@ Under `/var/lib/hyperhive/agents/<name>/`:
     has a value.
   - `hyperhive-harness.json` — rate-limited / needs-login flags read
     by the dashboard's async container-state fetch. See
-    `docs/2-handbook/hives/dashboard.md::Container row`.
+    `docs/4-implementation/web-ui/dashboard.md::Container row`.
 
   The agent writes its own instructions to `AGENTS.md` here; claude and
   opencode load it automatically from their cwd, `state/`. At boot,