feat(standalone): bottom-right version + source badge

A small fixed bottom-right overlay (VersionBadge) shown app-wide — on the home
page AND inside the loaded editor — surfacing this build's release tag and a
link to the source. The tag links to the exact commit when known (the pcbjam
commit pins the kicad + wxwidgets submodule revisions → our GPLv3
corresponding-source pointer, mirroring site Footer's BUILD_SHA), else the tag's
release page, else the repo root.

build-demo.mjs injects VITE_APP_TAG / VITE_GIT_SHA / VITE_REPO_URL (new --repo
flag, defaults to github.com/emergence-engineering/pcbjam).

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

web/standalone/src/App.tsx

@@ -1,4 +1,5 @@
 import { Route, Routes } from "react-router-dom";
+import { VersionBadge } from "@/components/VersionBadge";
 import { HomePage } from "@/pages/HomePage";
 import { LibToolPage } from "@/pages/LibToolPage";
 import { ProjectView } from "@/pages/ProjectView";
@@ -6,11 +7,15 @@ import { ToolPage } from "@/pages/ToolPage";
 
 export default function App() {
   return (
-    <Routes>
-      <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>
+    <>
+      <Routes>
+        <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>
+      {/* Version + source link, bottom-right on every route (home + editor). */}
+      <VersionBadge />
+    </>
   );
 }

web/standalone/src/components/VersionBadge.tsx

@@ -0,0 +1,49 @@
+import { Github } from "lucide-react";
+import { APP_GIT_SHA, APP_TAG, REPO_URL } from "@/lib/config";
+
+/**
+ * Small bottom-right overlay showing this build's version + a link to the
+ * source. The standalone is GPLv3, so the tag links to the exact commit
+ * (corresponding-source pointer — the repo commit pins the kicad + wxwidgets
+ * submodule revisions) when known, else the tag's release page, else the repo
+ * root. Mounted app-wide (App.tsx) so it shows on the home page AND inside the
+ * loaded editor. `fixed` keeps it viewport-anchored on every route; z-20 sits
+ * under the editor's boot overlay (z-30) so it's hidden until the tool is up.
+ */
+export function VersionBadge() {
+  const tag = APP_TAG ?? "dev";
+  const versionUrl = APP_GIT_SHA
+    ? `${REPO_URL}/commit/${APP_GIT_SHA}`
+    : APP_TAG
+      ? `${REPO_URL}/releases/tag/${APP_TAG}`
+      : REPO_URL;
+  const versionTitle = APP_GIT_SHA
+    ? `commit ${APP_GIT_SHA.slice(0, 12)} — GPL corresponding source`
+    : APP_TAG
+      ? `release ${APP_TAG}`
+      : "source repository";
+
+  return (
+    <div className="fixed bottom-3 right-3 z-20 flex items-center gap-2 rounded bg-black/70 px-2.5 py-1 font-mono text-[11px] text-white/80 shadow">
+      <a
+        href={versionUrl}
+        target="_blank"
+        rel="noreferrer"
+        title={versionTitle}
+        className="hover:text-white"
+      >
+        pcbjam {tag}
+      </a>
+      <span className="text-white/30">·</span>
+      <a
+        href={REPO_URL}
+        target="_blank"
+        rel="noreferrer"
+        title="Source on GitHub"
+        className="inline-flex items-center gap-1 hover:text-white"
+      >
+        <Github size={12} /> source
+      </a>
+    </div>
+  );
+}

web/standalone/src/lib/config.ts

@@ -24,6 +24,26 @@ export const WASM_MANIFEST_FILE = import.meta.env.VITE_WASM_MANIFEST || null;
 /** @deprecated Use WASM_ROOT + resolveWasmBase(). Kept for back-compat. */
 export const WASM_ASSET_BASE_URL = WASM_ROOT;
 
+// --- build identity (version badge + GPLv3 corresponding-source pointer) -------
+// The standalone is GPLv3; the badge surfaces the build's tag + a link to the
+// exact source. The repo commit pins the kicad + wxwidgets submodule revisions,
+// so APP_GIT_SHA → github.com/.../commit/<sha> is our corresponding-source
+// pointer (mirrors site/src/components/Footer.astro's BUILD_SHA). All three are
+// injected at build time by scripts/deploy/build-demo.mjs; unset in a plain dev
+// checkout (badge then shows "dev" → repo root).
+
+/** Release tag for this build (e.g. "2.7.7"); shown in the version badge. */
+export const APP_TAG = import.meta.env.VITE_APP_TAG || null;
+
+/** Source commit this build was made from; the badge links to it as the GPLv3
+ *  corresponding-source pointer. */
+export const APP_GIT_SHA = import.meta.env.VITE_GIT_SHA || null;
+
+/** Public source repository for the GPL editor (no trailing slash). */
+export const REPO_URL = (
+  import.meta.env.VITE_REPO_URL || "https://github.com/emergence-engineering/pcbjam"
+).replace(/\/+$/, "");
+
 /**
  * Where the standalone reads PROJECTS from (env VITE_PROJECT_SOURCE):
  *   "remote" (default) — the @pcbjam/shared REST backend at API_BASE_URL.

web/standalone/src/vite-env.d.ts

@@ -6,6 +6,12 @@ interface ImportMetaEnv {
   readonly VITE_WASM_ROOT?: string;
   /** Per-release WASM manifest file under VITE_WASM_ROOT (e.g. "manifest-2.7.7.json"); enables versioned per-tool folders. */
   readonly VITE_WASM_MANIFEST?: string;
+  /** Release tag for this build (e.g. "2.7.7"); shown in the version badge. */
+  readonly VITE_APP_TAG?: string;
+  /** Source commit this build was made from; the badge links to it as the GPLv3 corresponding-source pointer. */
+  readonly VITE_GIT_SHA?: string;
+  /** Public source repo URL for the GPL editor (default github.com/emergence-engineering/pcbjam). */
+  readonly VITE_REPO_URL?: string;
   /** @deprecated legacy alias for VITE_WASM_ROOT. */
   readonly VITE_WASM_ASSET_BASE_URL?: string;
   /** Project source: "remote" (default, REST backend) | "static" (read-only CDN gallery, no backend). */