feat(files): store files on the host when a channel has no file domain

Chat stays usable when the file service is off or down. Files up to 256 MB are hosted like chat; downloads try the host first and fall back to file-service tickets.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com> [CI]

web/src/worker/space/channelEvents.ts

@@ -10,7 +10,7 @@ import type { FileItem, Item, SenderInfo, Snapshot } from '@/domain/types';
 import { previewKindOf } from '@/lib/files/fileKind';
 import { blobs, readers } from '../runtime/sessions';
 import { showRejected, publishWorkspace } from '../runtime/presentation';
-import { type ChannelWire, toChannelInfo } from '../runtime/wire';
+import type { ChannelWire } from '../runtime/wire';
 import { channelInfo } from './spaceAvatars';
 import { apiFetch, readJson } from '../runtime/http';
 import { readResourceRecord } from './workspaceRecords';

web/src/worker/space/channelResources.ts

@@ -13,7 +13,7 @@ import { attachDataKeys, initializeChannelKeys } from '../crypto/channelDataKeys
 import type { ChannelSettingsPatch as SettingsRequest, JoinResult, MemberBody } from '@/api/generated';
 import { freshlyJoined, getSession, sessions } from '../runtime/sessions';
 import { makeLink } from './links';
-import { toChannelInfo, type ChannelWire } from '../runtime/wire';
+import type { ChannelWire } from '../runtime/wire';
 import { channelInfo } from './spaceAvatars';
 import { stopChannel } from './channelTransport';
 import { publishWorkspace } from '../runtime/presentation';