a plugin screen can declare its routes

Every screen got `/<route>` and `/<route>/:section` and nothing deeper, so a
section had to live in the query string. A screen may now name its routes in
the manifest, and give one its own arrangement of the screen's panels.

Absent, the old pair is unchanged — which is every plugin but fofos-admin.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/servers/plugins/discover.ts

@@ -1,5 +1,5 @@
 import { existsSync, readdirSync, statSync } from 'node:fs';
-import { join } from 'node:path';
+import { join, sep } from 'node:path';
 import { PLATFORM_DIR } from '../data-path';
 import {
   manifestProblems,
@@ -93,10 +93,14 @@ function findWeb(
           `Every plugin route renders a Workspace: contribute panels and a layout, not a screen.`,
       };
     }
+    const problems: string[] = [];
+    const routes = routesOf(manifest?.routes, webDir, layout, problems);
+    if (problems.length) return { web: null, error: `${appName}: ${problems.join('; ')}.` };
+
     return {
       web: {
         screens: [
-          { segment: null, label: manifest?.label ?? appName, icon: manifest?.icon, art: null, panels, layout },
+          { segment: null, label: manifest?.label ?? appName, icon: manifest?.icon, art: null, panels, layout, routes },
         ],
         // Optional and unannounced — presence is the declaration, as it is for panels and layout.
         fileActions: fileOrNull(join(webDir, 'file-actions.ts')),
@@ -145,6 +149,8 @@ function findWeb(
       art: fileOrNull(join(dir, 'assets', `${screen.segment}.png`)),
       panels,
       layout,
+      // On the screen entry, not the manifest root: a route belongs to the screen it renders inside.
+      routes: routesOf(screen.routes, join(webDir, screen.segment), layout, problems),
     });
   }
 
@@ -162,6 +168,52 @@ function findWeb(
   return { web: { screens, fileActions: fileOrNull(join(webDir, 'file-actions.ts')) } };
 }
 
+/**
+ * A screen's route table, resolved against the plugin directory.
+ *
+ * ── Every layout is checked HERE ──
+ *
+ * A route naming a file that is not there would be a build error in generated code — a stack trace
+ * pointing at `Plugins.gen.tsx`, which nobody wrote. Refused at discovery it is a sentence naming the
+ * plugin and the missing file, which is the same trade every other check in this file makes.
+ *
+ * A path is not validated beyond being a string: it is react-router's syntax, not ours, and a
+ * half-understood copy of their grammar would refuse patterns that work.
+ */
+function routesOf(
+  declared: { path: string; layout?: string }[] | undefined,
+  webDir: string,
+  fallbackLayout: string,
+  problems: string[],
+): { path: string; layout: string }[] {
+  const seen = new Set<string>();
+  const routes: { path: string; layout: string }[] = [];
+
+  for (const route of declared ?? []) {
+    // Two entries on one path is one of them never matching, silently — react-router takes the first.
+    if (seen.has(route.path)) {
+      problems.push(`route ${JSON.stringify(route.path)} is declared twice`);
+      continue;
+    }
+    seen.add(route.path);
+
+    if (!route.layout) {
+      routes.push({ path: route.path, layout: fallbackLayout });
+      continue;
+    }
+    // Under web/, like everything else a screen declares. `join` on a traversal would leave the plugin
+    // directory, so the resolved path is checked to still be inside it.
+    const resolved = join(webDir, route.layout.replace(/^web\//, ''));
+    if (!resolved.startsWith(webDir + sep) || !existsSync(resolved)) {
+      problems.push(`route ${JSON.stringify(route.path)} names layout ${JSON.stringify(route.layout)}, which is not in web/`);
+      continue;
+    }
+    routes.push({ path: route.path, layout: resolved });
+  }
+
+  return routes;
+}
+
 const fileOrNull = (path: string): string | null => (existsSync(path) ? path : null);
 
 /**