feat(acl): redesign ACL with conversation scope selector (#297)

Backend
- New subject kinds: all / channel_identity / channel_type
- Source scope fields on bot_acl_rules: source_channel,
  source_conversation_type, source_conversation_id, source_thread_id
- Fix source_scope_check constraint: resolve source_channel server-side
  (channel_type → subject_channel_type; channel_identity → DB lookup)
- Add GET /bots/:id/acl/channel-types/:type/conversations to list
  observed conversations by platform type
- ListObservedConversations: include private/DM chats, normalise
  conversation_type; COALESCE(name, handle) for display name
- enrichConversationAvatar: persist entry.Name → conversation_name
  (keeps Telegram group titles current on every message)
- Unify Priority type to int32 across Go types to match DB INTEGER;
  remove all int/int32 casts in service layer
- Fix duplicate nil guard in Evaluate; drop dead SourceScope.Channel field
- Migration 0048_acl_redesign

Frontend
- Drag-and-drop rule priority reordering (SortableJS/useSortable);
  fix reorder: compute new order from oldIndex/newIndex directly,
  not from the array (which useSortable syncs after onEnd)
- Conversation scope selector: searchable popover backed by observed
  conversations (by identity or platform type); collapsible manual-ID fallback
- Display: name as primary label, stable channel·type·id always shown
  as subtitle for verification
- bot-terminal: accessibility fix on close-tab button (keyboard events)
- i18n: drag-to-reorder, conversation source, manual IDs (en/zh)

Tests: update fakeChatACL to Evaluate interface; fix SourceScope literals.
SDK/spec regenerated.

apps/web/package.json

@@ -23,6 +23,7 @@
     "@tanstack/vue-table": "^8.21.3",
     "@vee-validate/zod": "^4.15.1",
     "@vueuse/core": "^14.1.0",
+    "@vueuse/integrations": "^14.2.1",
     "@xterm/addon-fit": "^0.11.0",
     "@xterm/addon-serialize": "^0.14.0",
     "@xterm/xterm": "^6.0.0",
@@ -38,6 +39,7 @@
     "pinia-plugin-persistedstate": "^4.7.1",
     "qrcode": "^1.5.4",
     "shiki": "^3.21.0",
+    "sortablejs": "^1.15.7",
     "stream-markdown": "^0.0.13",
     "stream-monaco": "^0.0.18",
     "tailwindcss": "^4.2.2",