finish phase 3: type-only codemod and zero non-bridge @atproto/api imports

Task 8: codemod repointed 150 namespace-type files to #/lexicons
(AppBskyFeedDefs.PostView -> app.bsky.feed.defs.PostView, .Record -> .Main)
plus ~105 hand-fixed consumers (composer/video state, DebugMod, Profile,
onboarding, dialogs). DM_SERVICE_HEADERS deleted; last chat call sites on
the chat client. RichText.tsx flipped to SDK-only. Remaining @atproto/api
importers: the three session bridge files, the deliberate dual-world
matcher in lib/xrpc-error.ts, and test fixtures. toLex boundary casts are
TODO(phase4)-tagged for bridge removal.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/components/Post/Embed/StandardSiteEmbed/publishers.ts

@@ -1,8 +1,7 @@
-import {type AppBskyEmbedExternal} from '@atproto/api'
-
 import {Leaflet} from '#/components/icons/community/Leaflet'
 import {Offprint} from '#/components/icons/community/Offprint'
 import {Pckt} from '#/components/icons/community/Pckt'
+import {type app} from '#/lexicons'
 
 export type StandardSitePublisher = {
   host: string
@@ -25,7 +24,7 @@ function hostFromUri(uri: string | undefined): string | null {
 }
 
 export function getStandardSitePublisherHost(
-  view: AppBskyEmbedExternal.ViewExternal,
+  view: app.bsky.embed.external.ViewExternal,
 ): string | null {
   return hostFromUri(view.source?.uri)
 }
@@ -40,7 +39,7 @@ function matchByHost(host: string | null): StandardSitePublisher | null {
 }
 
 export function matchStandardSitePublisher(
-  view: AppBskyEmbedExternal.ViewExternal,
+  view: app.bsky.embed.external.ViewExternal,
 ): StandardSitePublisher | null {
   return matchByHost(getStandardSitePublisherHost(view))
 }