From 73e4419aaa9ad5d9fd2ba69c375fb600c5eea29a Mon Sep 17 00:00:00 2001
From: Lu Wilson <lu@todepond.com>
Date: Tue, 19 May 2026 14:51:51 +0100
Subject: [PATCH 1/3] test preview

---
 src/prototypes/index.vue | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/prototypes/index.vue b/src/prototypes/index.vue
index 17c89e5..8f0cf1c 100644
--- a/src/prototypes/index.vue
+++ b/src/prototypes/index.vue
@@ -88,7 +88,7 @@ const showBucketDivider = computed(
 </script>
 
 <template>
-  <PlainWrapper heading="ProtoWiki">
+  <PlainWrapper heading="ProtoWiki preview test">
     <div class="prototype-index">
       <div class="prototype-index__list">
         <div v-for="entry in regularPrototypes" :key="entry.path" class="prototype-index__card">

From 4ca2a6ad4fe9d2a2749b31654a091386dc4f6be1 Mon Sep 17 00:00:00 2001
From: Lu Wilson <lu@todepond.com>
Date: Tue, 19 May 2026 15:02:48 +0100
Subject: [PATCH 2/3] it works??

---
 src/prototypes/index.vue | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/prototypes/index.vue b/src/prototypes/index.vue
index 8f0cf1c..4d966c6 100644
--- a/src/prototypes/index.vue
+++ b/src/prototypes/index.vue
@@ -88,7 +88,7 @@ const showBucketDivider = computed(
 </script>
 
 <template>
-  <PlainWrapper heading="ProtoWiki preview test">
+  <PlainWrapper heading="ProtoWiki preview test (it works!)">
     <div class="prototype-index">
       <div class="prototype-index__list">
         <div v-for="entry in regularPrototypes" :key="entry.path" class="prototype-index__card">

From c2467a4fb422e2fa758eae1813f442d5936f2935 Mon Sep 17 00:00:00 2001
From: Lu Wilson <lu@todepond.com>
Date: Tue, 19 May 2026 16:36:26 +0100
Subject: [PATCH 3/3] MAYBE FIX PREVIEW

---
 .agents/skills/protowiki-deploy/SKILL.md |  8 +++++---
 public/gh-pages-preview-404.js           |  7 +++++--
 src/lib/githubPagesPreviewRoute.ts       | 26 ++++++++++++++++++++++++
 src/main.ts                              |  3 +++
 4 files changed, 39 insertions(+), 5 deletions(-)
 create mode 100644 src/lib/githubPagesPreviewRoute.ts

diff --git a/.agents/skills/protowiki-deploy/SKILL.md b/.agents/skills/protowiki-deploy/SKILL.md
index d004722..52a9a3a 100644
--- a/.agents/skills/protowiki-deploy/SKILL.md
+++ b/.agents/skills/protowiki-deploy/SKILL.md
@@ -166,9 +166,11 @@ into review tickets to pin a specific preview.
 - **Preview deep link shows the gallery with `?template-…` in the URL.** That was
   an older `?/` redirect experiment; current builds use `sessionStorage` and should
   end on `…/pr-N/template-…` with no query hack.
-- **Preview deep link always lands on the gallery (URL is only `…/pr-N/`).** Usually
-  `gh-pages-restore.js` ran on root `404.html` and cleared `sessionStorage` before
-  the redirect finished — ensure restore skips pr-preview deep paths on the 404 page.
+- **Preview deep link always lands on the gallery (URL is only `…/pr-N/`).** Check that
+  root `404.html` includes the pr-preview preamble and that restore skips deep paths on
+  the 404 page (so `sessionStorage` survives). The preamble must also stop the
+  **production** bundle in `404.html` from booting (wrong `PROTOWIKI_BASE`); only the
+  preview `index.html` should run Vue.
 - **Asset URLs missing the base path.** Check `import.meta.env.BASE_URL`
   matches the deployed URL prefix; the router uses it.
 - **Blank app on Pages or preview.** Wrong `PROTOWIKI_BASE` (missing repo
diff --git a/public/gh-pages-preview-404.js b/public/gh-pages-preview-404.js
index c8ed50b..95d74a9 100644
--- a/public/gh-pages-preview-404.js
+++ b/public/gh-pages-preview-404.js
@@ -2,7 +2,7 @@
 // serves 404.html at the site root; deep links under pr-preview/pr-N/... hit
 // that file with the production base. Redirect into the preview base and stash
 // the path for gh-pages-restore.js on the preview index.
-;(function (l) {
+;(function (l, doc) {
   var m = l.pathname.match(/^(.+\/pr-preview\/pr-\d+)\/?(.*)$/)
   if (!m) return
   var base = m[1] + '/'
@@ -12,5 +12,8 @@
     'protowiki-gh-pages-path',
     path + (l.search || '') + (l.hash || ''),
   )
+  // Do not let the production SPA in this file boot (wrong PROTOWIKI_BASE).
+  doc.documentElement.innerHTML =
+    '<head><meta charset="utf-8"><title>ProtoWiki</title></head><body></body>'
   l.replace(base)
-})(location)
+})(location, document)
diff --git a/src/lib/githubPagesPreviewRoute.ts b/src/lib/githubPagesPreviewRoute.ts
new file mode 100644
index 0000000..7dff761
--- /dev/null
+++ b/src/lib/githubPagesPreviewRoute.ts
@@ -0,0 +1,26 @@
+import type { Router } from 'vue-router'
+
+/** Path under `import.meta.env.BASE_URL` (e.g. `/template-chrome`). */
+export function githubPagesSubpathAfterBase(baseUrl: string): string | null {
+  const basePrefix = baseUrl.endsWith('/') ? baseUrl.slice(0, -1) : baseUrl
+  let subPath = window.location.pathname
+  if (basePrefix && subPath.startsWith(basePrefix)) {
+    subPath = subPath.slice(basePrefix.length)
+  }
+  if (!subPath || subPath === '/') {
+    return null
+  }
+  return subPath.startsWith('/') ? subPath : `/${subPath}`
+}
+
+/**
+ * After gh-pages-restore.js updates the URL, ensure Vue Router matches the deep
+ * path (replaceState alone is not always enough on first paint).
+ */
+export function syncGithubPagesPreviewRoute(router: Router): void {
+  const subPath = githubPagesSubpathAfterBase(import.meta.env.BASE_URL)
+  if (!subPath) {
+    return
+  }
+  void router.replace(subPath)
+}
diff --git a/src/main.ts b/src/main.ts
index 127f10e..a46d838 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -11,6 +11,7 @@ import './styles/wiki-content/minerva.css'
 import './styles/wiki-content/mobile-wiki-overrides.css'
 import './styles/dark.css'
 
+import { syncGithubPagesPreviewRoute } from './lib/githubPagesPreviewRoute'
 import { initTheming } from './lib/theming'
 
 initTheming()
@@ -20,6 +21,8 @@ const router = createRouter({
   routes,
 })
 
+syncGithubPagesPreviewRoute(router)
+
 if (import.meta.hot) {
   handleHotUpdate(router)
 }