chore(deps): pin foliate-js to d4d87a9 via canonical https URL

Switch the @bookhoard/foliate-js dependency from the github: shorthand
(d164d6f) to the explicit git+https URL form (d4d87a9). The newer
revision is required by the double-page-spread support (renderer
'spread' attribute) and the explicit URL form resolves more reliably
across npm/podman builds.

package.json

@@ -12,7 +12,7 @@
     "dev": "npm run build:ts:dev && npm run build:css"
   },
   "dependencies": {
-    "@bookhoard/foliate-js": "github:john-okeefe/foliate-js#d164d6f",
+    "@bookhoard/foliate-js": "git+https://github.com/john-okeefe/foliate-js.git#d4d87a9",
     "alpinejs": "^3.15.8",
     "chart.js": "^4.5.1",
     "highlight.js": "^11.11.1",