restore compile-time error matching with isXrpcErrorOf

The migration replaced typed error classes (e instanceof
SomeNsid.SomeError) with getErrorName(e) === 'X' string comparisons,
where a typo'd or undeclared name compiles silently. isXrpcErrorOf
(method, e, name) constrains name to InferMethodError<M> - the errors
tuple the generated lexicon schema declares - restoring the old
compile-time guarantee (verified: a typo'd name fails typecheck).
47 comparison sites across 16 files migrated.

Deliberately left on getErrorName, with comments:
- LoginForm AuthFactorTokenRequired: a LexAuthFactorError from
  PasswordSession.login, not an XrpcError.
- AppealForm AlreadyAppealed: createReport declares NO errors in its
  lexicon; the server sends it anyway (undeclared behavior worth
  raising upstream).
- PostFeedErrorMessage Block detection: generic over feed descriptors,
  source method genuinely ambiguous.
- isErrorMaybeAppPasswordPermissions: generic InvalidToken + message.

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

src/components/dms/LeaveConvoPrompt.tsx

@@ -3,12 +3,13 @@ import {StackActions, useNavigation} from '@react-navigation/native'
 
 import {type NavigationProp} from '#/lib/routes/types'
 import {isNetworkError} from '#/lib/strings/errors'
-import {getErrorName} from '#/lib/xrpc-error'
+import {isXrpcErrorOf} from '#/lib/xrpc-error'
 import {useLeaveConvo} from '#/state/queries/messages/leave-conversation'
 import {type DialogOuterProps} from '#/components/Dialog'
 import * as Prompt from '#/components/Prompt'
 import * as Toast from '#/components/Toast'
 import {IS_NATIVE} from '#/env'
+import {chat} from '#/lexicons'
 
 export function LeaveConvoPrompt({
   control,
@@ -36,9 +37,13 @@ export function LeaveConvoPrompt({
       let errorMessage = l`Could not leave chat`
       if (isNetworkError(error)) {
         errorMessage = l`A network error occurred. Please check your internet connection.`
-      } else if (getErrorName(error) === 'InvalidConvo') {
+      } else if (
+        isXrpcErrorOf(chat.bsky.convo.leaveConvo, error, 'InvalidConvo')
+      ) {
         errorMessage = l`Conversation not found.`
-      } else if (getErrorName(error) === 'OwnerCannotLeave') {
+      } else if (
+        isXrpcErrorOf(chat.bsky.convo.leaveConvo, error, 'OwnerCannotLeave')
+      ) {
         errorMessage = l`Owner must lock the group before leaving.`
       }
       Toast.show(errorMessage, {type: 'error'})