collapse the dual-world type layer and delete the widening shims

The types/bsky post/profile/starterPack unions drop their @atproto/api arms,
and dangerousIsType/validate go with the old-world guards they wrapped. The
moderation subjects.ts widening shim and rich-text-helpers' asSdkFacets both
existed only to bridge branded and unbranded views, so their 55 and 14 callers
now go straight to @bsky.app/sdk/moderation and the raw facets.

Boundary fallout: lexicon token defs are camelCase schema objects needing
.value, and the branded string slots that the widening used to absorb are now
cast or branded at their producers.

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

src/view/com/composer/Composer.tsx

@@ -44,7 +44,7 @@ import {useSafeAreaInsets} from 'react-native-safe-area-context'
 import {scheduleOnUI} from 'react-native-worklets'
 import * as FileSystem from 'expo-file-system'
 import {type ImagePickerAsset} from 'expo-image-picker'
-import {type Client} from '@atproto/lex'
+import {type Client, type UriString} from '@atproto/lex'
 import {type AtUriString, AtUri} from '@atproto/syntax'
 import {type RichText} from '@bsky.app/sdk/richtext'
 import {plural} from '@lingui/core/macro'
@@ -52,6 +52,7 @@ import {Trans, useLingui} from '@lingui/react/macro'
 import {useNavigation} from '@react-navigation/native'
 import {useQueries, useQueryClient} from '@tanstack/react-query'
 
+import {matchXrpcError} from '#/lib/xrpc-error'
 import * as bsky from '#/types/bsky'
 import * as apilib from '#/lib/api/index'
 import {EmbeddingDisabledError} from '#/lib/api/resolve'
@@ -766,7 +767,9 @@ export const ComposePost = ({
 
   const getDraftSaveError = useCallback(
     (e: unknown): string => {
-      if (e instanceof app.bsky.draft.createDraft.DraftLimitReachedError) {
+      if (
+        matchXrpcError(e, app.bsky.draft.createDraft) === 'DraftLimitReached'
+      ) {
         return l`You've reached the maximum number of drafts`
       }
       return l`Failed to save draft`
@@ -1676,7 +1679,7 @@ let ComposerPost = memo(function ComposerPost({
 
   const onNewLink = useCallback(
     (uri: string) => {
-      dispatchPost({type: 'embed_add_uri', uri})
+      dispatchPost({type: 'embed_add_uri', uri: uri as UriString})
     },
     [dispatchPost],
   )

src/view/com/composer/ExternalEmbed.tsx

@@ -1,3 +1,4 @@
+import {type UriString} from '@atproto/lex'
 import {useMemo} from 'react'
 import {type StyleProp, View, type ViewStyle} from 'react-native'
 
@@ -32,9 +33,9 @@ export const ExternalEmbedGif = ({
     () =>
       data && {
         title: data.title ?? data.uri,
-        uri: data.uri,
+        uri: data.uri as UriString,
         description: data.description ?? '',
-        thumb: data.thumb?.source.path,
+        thumb: data.thumb?.source.path as UriString | undefined,
       },
     [data],
   )
@@ -80,7 +81,7 @@ export const ExternalEmbedLink = ({
   hasQuote,
   onRemove,
 }: {
-  uri: string
+  uri: UriString
   hasQuote: boolean
   onRemove: () => void
 }) => {
@@ -100,7 +101,8 @@ export const ExternalEmbedLink = ({
                 description:
                   data.view?.external?.description || data.description,
                 // prefer opengraph data to atproto record-derived image
-                thumb: data.thumb?.source.path || data.view?.external?.thumb,
+                thumb: (data.thumb?.source.path ||
+                  data.view?.external?.thumb) as UriString | undefined,
               }}
             />
           )
@@ -111,7 +113,7 @@ export const ExternalEmbedLink = ({
               title: data.title || uri,
               uri,
               description: data.description,
-              thumb: data.thumb?.source.path,
+              thumb: data.thumb?.source.path as UriString | undefined,
             }}
             hideAlt
           />

src/view/com/composer/drafts/state/api.ts

@@ -1,6 +1,7 @@
 /**
  * Type converters for Draft API - convert between ComposerState and server Draft types.
  */
+import {type UriString} from '@atproto/lex'
 import {RichText} from '@bsky.app/sdk/richtext'
 import {nanoid} from 'nanoid/non-secure'
 
@@ -275,7 +276,7 @@ function serializeGif(gifMedia: {
 
   return {
     $type: 'app.bsky.draft.defs#draftEmbedExternal',
-    uri: url.toString(),
+    uri: url.toString() as UriString,
   }
 }
 
@@ -607,7 +608,7 @@ export async function draftToComposerPosts(
         const record = post.embedRecords[0]
         const urip = new AtUri(record.record.uri)
         const url = `https://bsky.app/profile/${urip.host}/post/${urip.rkey}`
-        embed.quote = {type: 'link', uri: url}
+        embed.quote = {type: 'link', uri: url as UriString}
       }
 
       // Restore link embed (only if not a GIF)

src/view/com/composer/state/composer.ts

@@ -1,3 +1,4 @@
+import {type UriString} from '@atproto/lex'
 import {type ImagePickerAsset} from 'expo-image-picker'
 import {type AtUriString, toDatetimeString} from '@atproto/syntax'
 import {RichText} from '@bsky.app/sdk/richtext'
@@ -55,7 +56,12 @@ type GifMedia = {
 
 type Link = {
   type: 'link'
-  uri: string
+  /*
+   * A URL the user typed or pasted, validated by the link resolver rather than
+   * at construction, so it carries lex's `uri` brand for the record and view
+   * slots it flows into.
+   */
+  uri: UriString
 }
 
 // This structure doesn't exactly correspond to the data model.
@@ -90,7 +96,7 @@ export type PostAction =
     }
   | {type: 'embed_remove_video'}
   | {type: 'embed_update_video'; videoAction: VideoAction}
-  | {type: 'embed_add_uri'; uri: string}
+  | {type: 'embed_add_uri'; uri: UriString}
   | {type: 'embed_remove_quote'}
   | {type: 'embed_remove_link'}
   | {type: 'embed_add_gif'; gif: Gif}
@@ -645,7 +651,7 @@ export function createComposerState({
     if (path) {
       quote = {
         type: 'link',
-        uri: toBskyAppUrl(path),
+        uri: toBskyAppUrl(path) as UriString,
       }
     }
   }
@@ -699,7 +705,7 @@ export function createComposerState({
     if (suggestedExtUri) {
       link = {
         type: 'link',
-        uri: suggestedExtUri,
+        uri: suggestedExtUri as UriString,
       }
     }
     const suggestedPostUri = suggestLinkCardUri(
@@ -716,7 +722,7 @@ export function createComposerState({
       if (!quote) {
         quote = {
           type: 'link',
-          uri: suggestedPostUri,
+          uri: suggestedPostUri as UriString,
         }
       }
     }