docs(web-ui/agent): add back-link nav + fix stale doc pointer in screen.html

docs/web-ui/agent.md

@@ -338,7 +338,8 @@ shaped).
   would vendor noVNC; this file ships the minimal in-tree variant).
   Only accessible when `hyperhive.gui.enable = true` in the agent's
   `agent.nix`; the harness shows a 🖥 screen link in the state row
-  when `gui_vnc_port` is present. Toolbar: `⤢ fit` CSS-downscales
+  when `gui_vnc_port` is present. A `← agent` back-link in the page
+  header returns to the main per-agent page. Controls: `⤢ fit` CSS-downscales
   the canvas to the window via `relayoutCanvas()` setting explicit
   pixel dimensions on the canvas — *not* CSS `max-width/max-height`,
   because a flex item's automatic minimum size (`min-width: auto`
@@ -379,7 +380,8 @@ Bus events (new vocabulary on `/events/stream`):
 
 `GET /stats` is a separate per-agent page (served by the
 harness, linked from the per-agent page's `📊 stats →` and from
-each dashboard container row). Turn analytics, read-only, from
+each dashboard container row). A `← live` back-link in the page
+header returns to the main per-agent page. Turn analytics, read-only, from
 `/state/hyperhive-turn-stats.sqlite`. `GET /api/stats?window=
 24h|7d|30d|all` returns a time-bucketed `Snapshot`; the page renders
 it with Chart.js (bundled into `stats.js` via esbuild — no CDN

frontend/packages/agent/src/screen.html

@@ -25,9 +25,8 @@
 <script>
 // Minimal RFB-over-WebSocket renderer. Connects to `screen/ws` on
 // the same host; the harness relays raw RFB bytes to the VNC server
-// running inside the container. See docs/web-ui.md::Per-agent
-// endpoints (GET /screen) for the design rationale + canvas-sizing
-// implementation notes.
+// running inside the container. See docs/web-ui/agent.md (GET /screen)
+// for the design rationale + canvas-sizing implementation notes.
 
 (function () {
   'use strict';