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/screens/Messages/Conversation.tsx

@@ -1,7 +1,6 @@
 import {useCallback, useEffect, useMemo, useState} from 'react'
 import {type LayoutChangeEvent, View} from 'react-native'
 import {useSafeAreaInsets} from 'react-native-safe-area-context'
-import {ChatBskyConvoDefs} from '@atproto/api'
 import {
   ScrollEdgeEffect,
   ScrollEdgeEffectProvider,
@@ -46,7 +45,8 @@ import {type ConvoWithDetails, parseConvoView} from '#/components/dms/util'
 import {Error} from '#/components/Error'
 import * as Layout from '#/components/Layout'
 import {IS_LIQUID_GLASS} from '#/env'
-import {toLex} from '#/types/bsky'
+import {chat} from '#/lexicons'
+import {isType, toLex} from '#/types/bsky'
 import {ChatDisabled} from './components/ChatDisabled'
 import {ChatEnded} from './components/ChatEnded'
 import {ChatLocked} from './components/ChatLocked'
@@ -180,7 +180,8 @@ function InnerReady({
   const emailDialogControl = useEmailDialogControl()
 
   const unreadRequestCount =
-    convo?.kind === 'group' && ChatBskyConvoDefs.isGroupConvo(convo.view.kind)
+    convo?.kind === 'group' &&
+    isType(chat.bsky.convo.defs.groupConvo, convo.view.kind)
       ? (convo.view.kind.unreadJoinRequestCount ?? 0)
       : 0
   const {mutate: markJoinRequestsRead} = useMarkJoinRequestsRead(convo?.view.id)