fix: app-switcher routes through tab system + canvas fills viewport in tab pane

- App-switcher now dispatches module-select event instead of full page navigation
  for same-origin links; shell routes through TabCache for instant tab switching
- Tab pane gets height:100% in canvas-layout mode so #canvas fills the viewport
  (fixes pan/zoom not working on empty canvas background)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/shell.ts

@@ -324,6 +324,36 @@ export function renderShell(opts: ShellOptions): string {
         document.dispatchEvent(new CustomEvent('layer-view-mode', { detail: { mode } }));
       });
 
+      // ── App-switcher → tab system integration ──
+      // When user picks a module from the app-switcher, route through tabs
+      // instead of doing a full page navigation.
+      const appSwitcher = document.querySelector('rstack-app-switcher');
+      if (appSwitcher) {
+        appSwitcher.addEventListener('module-select', (e) => {
+          const { moduleId } = e.detail;
+          // Already on this module? No-op.
+          if (moduleId === currentModuleId && !tabCache) return;
+          if (moduleId === currentModuleId && tabCache) {
+            tabCache.switchTo(moduleId);
+            return;
+          }
+          // Add tab if not already open
+          if (!layers.find(l => l.moduleId === moduleId)) {
+            layers.push(makeLayer(moduleId, layers.length));
+          }
+          saveTabs();
+          tabBar.setLayers(layers);
+          tabBar.setAttribute('active', 'layer-' + moduleId);
+          if (tabCache) {
+            tabCache.switchTo(moduleId).then(ok => {
+              if (!ok) window.location.href = window.__rspaceNavUrl(spaceSlug, moduleId);
+            });
+          } else {
+            window.location.href = window.__rspaceNavUrl(spaceSlug, moduleId);
+          }
+        });
+      }
+
       // Expose tabBar for CommunitySync integration
       window.__rspaceTabBar = tabBar;
 

shared/components/rstack-app-switcher.ts

@@ -254,6 +254,27 @@ export class RStackAppSwitcher extends HTMLElement {
 			el.addEventListener("click", (e) => e.stopPropagation());
 		});
 
+		// Intercept same-origin module links → dispatch event for tab system
+		this.#shadow.querySelectorAll("a.item").forEach((el) => {
+			el.addEventListener("click", (e) => {
+				const moduleId = (el as HTMLElement).dataset.id;
+				if (!moduleId) return;
+				// Only intercept same-origin links (skip bare-domain landing pages)
+				const href = (el as HTMLAnchorElement).href;
+				try {
+					const url = new URL(href, window.location.href);
+					if (url.origin !== window.location.origin) return;
+				} catch { return; }
+				e.preventDefault();
+				menu.classList.remove("open");
+				this.dispatchEvent(new CustomEvent("module-select", {
+					detail: { moduleId },
+					bubbles: true,
+					composed: true,
+				}));
+			});
+		});
+
 		document.addEventListener("click", () => menu.classList.remove("open"));
 	}
 

website/public/shell.css

@@ -392,6 +392,11 @@ body[data-theme="light"] {
   display: block;
 }
 
+/* When canvas is active, the tab pane must fill the viewport so #canvas height:100% works */
+#app.canvas-layout > .rspace-tab-pane--active {
+  height: 100%;
+}
+
 .rspace-tab-loading {
   display: flex;
   align-items: center;