fix(adwright): route ↗BTE crosslink through canonical switchPanel

The Adwright ↗BTE button called SvrntyBTE.open() directly, which sets
overlay.hidden=false but never flips main.svrnty-showing-bte. The CSS
gates BTE overlay visibility on that class, so the click did nothing
visible — overlay was mounted but display:none. Route the click through
window.switchPanel("bte") instead so the canonical nav wrapper handles
class flipping + event dispatch identically to the sidebar BTE button.

Validated via Playwright with 6 gates: V1 sidebar BTE (1 event, class
set, visible), V2 ↗BTE crosslink (1 event, class flip, visible),
V3 Adwright nav (class flip, BTE hidden), V4 main classes correct,
V5 console clean, V6 /api/bte/proxy 200 OK. All pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

routes/umbrella.py

@@ -26,12 +26,18 @@ def _repo_root() -> Path:
 
 
 def register(api):
-    """Wire umbrella panel + APIs."""
+    """Wire umbrella panel + APIs.
+
+    Note: the panel HTML lives at /plugins/svrnty/umbrella.html (served via
+    register_static). The /umbrella top-level route would require a non-/api/
+    handler, which the plugin loader doesn't allow (see SVRNTY-PLUGIN-PROTOCOL
+    §5.1 — register_route only accepts /api/*). Frontend nav links directly to
+    /plugins/svrnty/umbrella.html.
+    """
     log = api.logger("svrnty.routes.umbrella")
-    api.register_route("/umbrella", "GET", _handle_panel_html)
     api.register_route("/api/umbrella", "GET", _handle_graph_json)
     api.register_route("/api/umbrella/doc", "GET", _handle_doc_body)
-    log.info("umbrella panel + APIs registered")
+    log.info("umbrella APIs registered")
 
 
 def _send(handler, status: int, body: bytes, content_type: str) -> None:
@@ -101,11 +107,3 @@ def _handle_doc_body(handler, parsed) -> bool:
     }).encode("utf-8")
     _send(handler, 200, body, "application/json; charset=utf-8")
     return True
-
-
-def _handle_panel_html(handler, parsed) -> bool:
-    """Serve the static umbrella.html via Location redirect (assets live in static/)."""
-    handler.send_response(302)
-    handler.send_header("Location", "/plugins/svrnty/umbrella.html")
-    handler.end_headers()
-    return True

static/adwright.js

@@ -154,10 +154,17 @@
         _activateTab(id);
       });
     });
-    // Cross-panel link to BTE Command Center.
+    // Cross-panel link to BTE Command Center. Route through canonical
+    // switchPanel so main.svrnty-showing-bte class gets flipped (CSS gates
+    // overlay visibility on that class). SvrntyBTE.open is fallback for
+    // the early-boot edge case where the nav wrapper isn't installed yet.
     const bteBtn = panel.querySelector("#svrntyAwOpenBte");
     if (bteBtn) bteBtn.addEventListener("click", () => {
-      if (window.SvrntyBTE && window.SvrntyBTE.open) window.SvrntyBTE.open();
+      if (typeof window.switchPanel === "function") {
+        window.switchPanel("bte", { fromRailClick: true });
+      } else if (window.SvrntyBTE && window.SvrntyBTE.open) {
+        window.SvrntyBTE.open();
+      }
     });
     // One-click profile switch to cmo-planb.
     const switchBtn = panel.querySelector("#svrntyAwSwitchCmo");