feat: /l/:libId/:tool lib-scoped route + fix lib items for fileless launches

Add a deep-linkable, reload-safe route /l/<libId>/<tool> (LibToolPage) that boots
the editor scoped to one backend library; the home page's lib chips become
anchors to it (full nav → clean Emscripten). Local lib FILES stay in-place
(bytes can't be URL-addressed).

Fix empty lib trees against a registry server: fileless/lib-scoped launches use
the placeholder projectId "local", which was sent as x-pcbjam-project — the
closed server then scoped its (0005 mirror) lib resolution to a non-existent
project and returned nothing. Suppress the project header for "local"; real
backend projects keep sending their uuid and keep project-scoped resolution.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/standalone/src/App.tsx

@@ -1,5 +1,6 @@
 import { Route, Routes } from "react-router-dom";
 import { HomePage } from "@/pages/HomePage";
+import { LibToolPage } from "@/pages/LibToolPage";
 import { ProjectView } from "@/pages/ProjectView";
 import { ToolPage } from "@/pages/ToolPage";
 
@@ -9,6 +10,7 @@ export default function App() {
       <Route path="/" element={<HomePage />} />
       <Route path="/p/:project" element={<ProjectView />} />
       <Route path="/p/:project/:tool/*" element={<ToolPage />} />
+      <Route path="/l/:lib/:tool" element={<LibToolPage />} />
     </Routes>
   );
 }

web/standalone/src/lib/config.ts

@@ -74,12 +74,18 @@ export function libsOwner(): string {
 
 export function libsSourceConfig(projectId?: string): LibsSource | null {
   const kind = import.meta.env.VITE_LIBS_SOURCE ?? "remote";
+  // "local" is the placeholder id for launches with no real backend project
+  // (local folder, tool grid, lib-scoped open). It is NOT a project on the
+  // backend, so don't send it as the project header — a registry server would
+  // scope its lib resolution (project-pinned mirrors) to a non-existent project
+  // and return nothing. Real backend projects pass their uuid and keep scoping.
+  const project = projectId && projectId !== "local" ? projectId : undefined;
   const base =
     kind === "off"
       ? null
       : kind === "static"
         ? staticLibsSource()
-        : remoteLibsSource(API_BASE_URL, libsOwner(), projectId);
+        : remoteLibsSource(API_BASE_URL, libsOwner(), project);
 
   // 0004-A spike: `?libwrite=1` adds one in-memory writable user SYMBOL lib so the
   // editor save path works with no backend (a dev/test aid). The real remote

web/standalone/src/pages/HomePage.tsx

@@ -3,8 +3,6 @@ import { Link } from "react-router-dom";
 import type { Lib, Tool } from "@pcbjam/shared";
 import { FolderOpen, Library, Loader2, Package } from "lucide-react";
 import { useLibs, useProjects } from "@/lib/api";
-import { libsSourceConfig } from "@/lib/config";
-import { scopedLibsSource } from "@/wasm/libs/scoped-source";
 import { localFileLibsSource } from "@/wasm/libs/local-file-source";
 import type { LibsSource } from "@/wasm/libs/source";
 import { downloadBytes } from "@/lib/download";
@@ -121,15 +119,6 @@ export function HomePage() {
     libsSource?: LibsSource | null;
   } | null>(null);
 
-  /** Open a backend library scoped to itself in its matching editor. */
-  const openScopedLib = (tool: Tool, lib: Lib) => {
-    const base = libsSourceConfig("local");
-    setLaunchedTool({
-      tool,
-      libsSource: base ? scopedLibsSource(base, lib.id) : undefined,
-    });
-  };
-
   // <input webkitdirectory> is non-standard; set it imperatively.
   React.useEffect(() => {
     if (inputRef.current) inputRef.current.setAttribute("webkitdirectory", "");
@@ -299,13 +288,13 @@ export function HomePage() {
             icon={<Library size={16} />}
             label="Symbols"
             query={symbolLibs}
-            onOpen={(lib) => openScopedLib("symbol_editor", lib)}
+            tool="symbol_editor"
           />
           <LibGroup
             icon={<Package size={16} />}
             label="Footprints"
             query={footprintLibs}
-            onOpen={(lib) => openScopedLib("footprint_editor", lib)}
+            tool="footprint_editor"
           />
         </div>
       </section>
@@ -314,21 +303,20 @@ export function HomePage() {
 }
 
 /**
- * One backend-library group (Symbols / Footprints): clickable chips that launch
- * the matching editor to browse the library. The editor lists ALL libs of that
- * kind in its own tree (lib-scoped open is a later iteration); clicking here
- * just opens the right tool.
+ * One backend-library group (Symbols / Footprints): each lib is a deep-link to
+ * `/l/<libId>/<tool>` (LibToolPage), which boots the editor scoped to that one
+ * library. A full navigation (anchor) gives Emscripten a clean page.
  */
 function LibGroup({
   icon,
   label,
   query,
-  onOpen,
+  tool,
 }: {
   icon: React.ReactNode;
   label: string;
   query: ReturnType<typeof useLibs>;
-  onOpen: (lib: Lib) => void;
+  tool: Tool;
 }) {
   const { data: libs, isLoading, error } = query;
   return (
@@ -352,10 +340,9 @@ function LibGroup({
       {libs && libs.length > 0 && (
         <div className="flex flex-wrap gap-2">
           {libs.map((lib) => (
-            <button
+            <a
               key={lib.id}
-              type="button"
-              onClick={() => onOpen(lib)}
+              href={`/l/${encodeURIComponent(lib.id)}/${tool}`}
               title={lib.description ?? undefined}
               className="inline-flex items-center gap-1.5 rounded-md border px-2.5 py-1 text-sm hover:bg-accent"
             >
@@ -365,7 +352,7 @@ function LibGroup({
                   {lib.itemCount}
                 </span>
               )}
-            </button>
+            </a>
           ))}
         </div>
       )}

web/standalone/src/pages/LibToolPage.tsx

@@ -0,0 +1,47 @@
+import { useParams } from "react-router-dom";
+import { toolSchema } from "@pcbjam/shared";
+import { libsSourceConfig } from "@/lib/config";
+import { scopedLibsSource } from "@/wasm/libs/scoped-source";
+import { WasmTool } from "@/components/WasmTool";
+import { PreflightGate } from "@/preflight/PreflightGate";
+
+/**
+ * Open one BACKEND library scoped to itself in its editor, addressed by URL:
+ *   /l/<libId>/<tool>        e.g. /l/Diode/symbol_editor
+ *
+ * Deep-linkable + reload-safe (unlike the home page's in-place lib launch). The
+ * editor boots with no project/files and a `scopedLibsSource` so its lib tree
+ * shows exactly this one library. (Local lib FILES can't be URL-addressed — they
+ * stay an in-place launch on the home page.)
+ */
+export function LibToolPage() {
+  const params = useParams();
+  const libId = params.lib ?? "";
+  const parsedTool = toolSchema.safeParse(params.tool);
+
+  if (!parsedTool.success) {
+    return (
+      <div className="container py-10 text-destructive">
+        Unknown tool: {params.tool}
+      </div>
+    );
+  }
+
+  const base = libsSourceConfig("local");
+  const libsSource = base ? scopedLibsSource(base, libId) : null;
+
+  return (
+    <PreflightGate>
+      <WasmTool
+        tool={parsedTool.data}
+        slug="local"
+        projectId="local"
+        files={[]}
+        libsSource={libsSource}
+        fetchBytes={async (relPath) => {
+          throw new Error(`no project file to fetch: ${relPath}`);
+        }}
+      />
+    </PreflightGate>
+  );
+}