Embed testbed with tweaks (#9115)

* Nightly source-language update

* add: test embed page for bskyembeds

* run prettier

* wip

* feat: use local dev for bskyembed test.html

* feat: commit generated files which i'm not sure about

* chore: add basic readme to bskyembed

* Revert "feat: commit generated files which i'm not sure about"

This reverts commit b891efdaa1fd7ddd4417bfd5267e861a25a93b0e.

* chore: revert change to bskyembed/.eslintrc.cjs

* chore: remove generated file from bskyweb/static

* chore: revert messages.po changes

* add dev-snippet command, add dev router

* Update README.md

* Update bskyembed/test.html

* change IS_DEV check to allow localhost

---------

Co-authored-by: APiligrim <28320272+APiligrim@users.noreply.github.com>
Co-authored-by: Anastasiya Uraleva <anastasiya@Anastasiyas-MacBook-Pro.local>
Co-authored-by: Anastasiya Uraleva <anastasiya@Mac.localdomain>
Co-authored-by: Elijah Seed-Arita <elijaharita@gmail.com>

bskyembed/snippet/embed.ts

@@ -3,9 +3,19 @@ interface Window {
   bluesky: {
     scan: (element?: Pick<Element, 'querySelectorAll'>) => void
   }
+  BSKY_DEV_EMBED_URL?: string
 }
 
-const EMBED_URL = 'https://embed.bsky.app'
+/**
+ * Allow url to be overwritten during development
+ */
+const IS_DEV =
+  window.location.protocol === 'file:' ||
+  window.location.hostname === 'localhost'
+const EMBED_URL =
+  IS_DEV && window.BSKY_DEV_EMBED_URL
+    ? window.BSKY_DEV_EMBED_URL
+    : 'https://embed.bsky.app'
 
 window.bluesky = window.bluesky || {
   scan,