Add starter pack embeds to posts (#4699)

* starter pack embeds

* revert test code

* Types

* add `BaseLink`

* precache on click

* rm log

* add a comment

* loading state

* top margin

---------

Co-authored-by: Dan Abramov <dan.abramov@gmail.com>

src/lib/strings/starter-pack.ts

@@ -96,7 +96,7 @@ export function createStarterPackUri({
 }: {
   did: string
   rkey: string
-}): string | null {
+}): string {
   return new AtUri(`at://${did}/app.bsky.graph.starterpack/${rkey}`).toString()
 }
 

src/lib/strings/url-helpers.ts

@@ -152,6 +152,30 @@ export function isBskyListUrl(url: string): boolean {
   return false
 }
 
+export function isBskyStartUrl(url: string): boolean {
+  if (isBskyAppUrl(url)) {
+    try {
+      const urlp = new URL(url)
+      return /start\/(?<name>[^/]+)\/(?<rkey>[^/]+)/i.test(urlp.pathname)
+    } catch {
+      console.error('Unexpected error in isBskyStartUrl()', url)
+    }
+  }
+  return false
+}
+
+export function isBskyStarterPackUrl(url: string): boolean {
+  if (isBskyAppUrl(url)) {
+    try {
+      const urlp = new URL(url)
+      return /starter-pack\/(?<name>[^/]+)\/(?<rkey>[^/]+)/i.test(urlp.pathname)
+    } catch {
+      console.error('Unexpected error in isBskyStartUrl()', url)
+    }
+  }
+  return false
+}
+
 export function isBskyDownloadUrl(url: string): boolean {
   if (isExternalUrl(url)) {
     return false