[SDK] Add refreshSession and migrate the session-pinned infra (#11381)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

src/lib/link-meta/link-meta.ts

@@ -1,4 +1,4 @@
-import {type AppBskyEmbedExternal, type AtpAgent} from '@atproto/api'
+import {type AppBskyEmbedExternal} from '@atproto/api'
 
 import {LINK_META_PROXY} from '#/lib/constants'
 import {getGiphyMetaUri} from '#/lib/strings/embed-player'
@@ -31,7 +31,6 @@ export interface LinkMeta {
 }
 
 export async function getLinkMeta(
-  agent: AtpAgent,
   url: string,
   timeout = 15e3,
 ): Promise<LinkMeta> {
@@ -80,9 +79,7 @@ export async function getLinkMeta(
 
   try {
     const response = await fetch(
-      `${LINK_META_PROXY(agent.serviceUrl.toString() || '')}${encodeURIComponent(
-        url,
-      )}`,
+      `${LINK_META_PROXY('')}${encodeURIComponent(url)}`,
       {signal: controller.signal},
     )