Task #511: Fully remove Chat feature

Destructive removal per user confirmation ("حذف نهائي ما يرجع").

Removed:
- API: routes/conversations.ts, schema/conversations.ts, all chat
  socket handlers in src/index.ts, /admin/users/:id/dependents/
  conversations+messages endpoints, conversation/message dependency
  counts in users/stats routes.
- Web: pages/chat.tsx, /chat route, dock chat filter, MessageSquare
  icon and messages StatCard on home, all chat-related UI in
  notifications + admin (dependency badges, delete-dialog rows,
  UserDependentConversations/Messages sections, count map keys).
- Locales: nav.chat, home.stats.messages, full chat.* block,
  admin.deleteUser conv/msgCount, admin.users.counts.conv/msg,
  admin.audit.unit.conversation_*/message_*, admin.dependents.user*.
- OpenAPI spec: tags, all /conversations/* paths, conv/msg dependent
  paths, related schemas (ConversationWithDetails, MessageWithSender,
  UserDependentConversation/MessageItem+Page, etc.), UserProfile and
  UserDeletionConflict conv/msg fields, HomeStats.unreadMessages.
  Regenerated client via orval.
- Database: dropped message_reads, messages,
  conversation_participants, conversations (CASCADE); deleted
  notifications with related_type='conversation' or type='chat';
  deleted apps row with slug='chat'; ran drizzle push-force.
- Seed: removed chat:access permission + user-role assignment +
  seeded chat app entry from scripts/src/seed.ts.
- Tests: deleted conversations-leave.test.mjs; cleaned chat refs from
  list-dependency-counts, delete-force-warnings, audit-log-coverage,
  and admin-inline-dependency-counts (e2e) — replaced chat dependents
  with note dependents where needed for force-delete coverage.

Notes preserved: notes.tsx noConversationsYet/conversationWith refer
to NOTE THREADS (not chat) and were intentionally NOT touched.

executive-meetings.ts not modified per replit.md restriction.
Pre-existing flaky test failures in executive-meetings/group/etc
suites remain unrelated to this task.

lib/api-client-react/src/generated/api.schemas.ts

@@ -197,14 +197,6 @@ Omitted from single-user responses (GET /users/:id, PATCH, etc).
 admin list endpoint (GET /users).
  */
   orderCount?: number;
-  /** Number of conversations created by this user. Populated only by the
-admin list endpoint (GET /users).
- */
-  conversationCount?: number;
-  /** Number of messages authored by this user. Populated only by the
-admin list endpoint (GET /users).
- */
-  messageCount?: number;
 }
 
 export interface UpdateUserBody {
@@ -371,8 +363,6 @@ export interface UserDeletionConflict {
   error: string;
   noteCount: number;
   orderCount: number;
-  conversationCount: number;
-  messageCount: number;
 }
 
 export interface AppDeletionConflict {
@@ -643,96 +633,6 @@ export interface BulkDeleteServiceOrdersResponse {
   failedIds: number[];
 }
 
-export interface ParticipantInfo {
-  id: number;
-  username: string;
-  /** @nullable */
-  displayNameAr?: string | null;
-  /** @nullable */
-  displayNameEn?: string | null;
-  /** @nullable */
-  avatarUrl?: string | null;
-  isAdmin: boolean;
-}
-
-export type MessageWithSenderKind =
-  (typeof MessageWithSenderKind)[keyof typeof MessageWithSenderKind];
-
-export const MessageWithSenderKind = {
-  user: "user",
-  group_renamed: "group_renamed",
-  members_added: "members_added",
-  member_removed: "member_removed",
-  member_left: "member_left",
-  admin_promoted: "admin_promoted",
-} as const;
-
-export type MessageWithSenderMeta = { [key: string]: unknown } | null;
-
-export interface MessageWithSender {
-  id: number;
-  conversationId: number;
-  senderId: number;
-  content: string;
-  kind: MessageWithSenderKind;
-  meta?: MessageWithSenderMeta;
-  sender: ParticipantInfo;
-  createdAt: string;
-  updatedAt: string;
-}
-
-export interface ConversationWithDetails {
-  id: number;
-  /** @nullable */
-  nameAr?: string | null;
-  /** @nullable */
-  nameEn?: string | null;
-  /** @nullable */
-  avatarUrl?: string | null;
-  isGroup: boolean;
-  createdBy: number;
-  participants: ParticipantInfo[];
-  lastMessage?: MessageWithSender | null;
-  unreadCount: number;
-  isMuted: boolean;
-  isArchived: boolean;
-  createdAt: string;
-  updatedAt: string;
-}
-
-export interface CreateConversationBody {
-  participantIds: number[];
-  /** @nullable */
-  nameAr?: string | null;
-  /** @nullable */
-  nameEn?: string | null;
-  /** @nullable */
-  avatarUrl?: string | null;
-  isGroup?: boolean;
-}
-
-export interface UpdateConversationBody {
-  /** @nullable */
-  avatarUrl?: string | null;
-  /** @nullable */
-  nameAr?: string | null;
-  /** @nullable */
-  nameEn?: string | null;
-}
-
-export interface UpdateConversationStateBody {
-  isMuted?: boolean;
-  isArchived?: boolean;
-}
-
-export interface AddParticipantsBody {
-  userIds: number[];
-}
-
-export interface SendMessageBody {
-  content: string;
-}
-
 export interface Notification {
   id: number;
   userId: number;
@@ -808,7 +708,6 @@ export interface HomeStats {
   totalApps: number;
   totalServices: number;
   unreadNotifications: number;
-  unreadMessages: number;
   totalUsers: number;
 }
 
@@ -1224,47 +1123,6 @@ export interface UserDependentOrdersPage {
   nextOffset: number | null;
 }
 
-export interface UserDependentConversationItem {
-  id: number;
-  /** @nullable */
-  nameAr: string | null;
-  /** @nullable */
-  nameEn: string | null;
-  isGroup: boolean;
-  createdAt: string;
-}
-
-export interface UserDependentConversationsPage {
-  items: UserDependentConversationItem[];
-  totalCount: number;
-  limit: number;
-  offset: number;
-  /** @nullable */
-  nextOffset: number | null;
-}
-
-export interface UserDependentMessageItem {
-  id: number;
-  content: string;
-  kind: string;
-  createdAt: string;
-  conversationId: number;
-  /** @nullable */
-  conversationNameAr: string | null;
-  /** @nullable */
-  conversationNameEn: string | null;
-  conversationIsGroup: boolean;
-}
-
-export interface UserDependentMessagesPage {
-  items: UserDependentMessageItem[];
-  totalCount: number;
-  limit: number;
-  offset: number;
-  /** @nullable */
-  nextOffset: number | null;
-}
-
 export interface AuditLogActor {
   id: number;
   username: string;
@@ -1381,14 +1239,6 @@ export type DeleteServiceParams = {
   force?: boolean;
 };
 
-export type LeaveConversationBody = {
-  /** When the leaver is the only admin, optionally name a specific
-remaining member to promote. Omit (or send null) to keep the
-automatic behavior of promoting the longest-tenured member.
- */
-  successorId?: number | null;
-};
-
 export type ListUsersParams = {
   /**
    * Free-text search across username, email, and display names
@@ -1822,27 +1672,3 @@ export type GetAdminUserDependentOrdersParams = {
    */
   offset?: number;
 };
-
-export type GetAdminUserDependentConversationsParams = {
-  /**
-   * @minimum 1
-   * @maximum 200
-   */
-  limit?: number;
-  /**
-   * @minimum 0
-   */
-  offset?: number;
-};
-
-export type GetAdminUserDependentMessagesParams = {
-  /**
-   * @minimum 1
-   * @maximum 200
-   */
-  limit?: number;
-  /**
-   * @minimum 0
-   */
-  offset?: number;
-};