feat: email provider, admin password reset, portal new-patient, chat pill

Chat: history pill now shows a History icon + a Start-new-chat (SquarePen)
button; removed the duplicate chat-history list from the sidebar.

Email: deployment-wide email provider config (Resend/Postmark/SendGrid/SMTP) in
Settings → Developers, with encrypted API key and a Send-test action. sendEmail
dispatches via the chosen provider (REST via fetch; SMTP via nodemailer).

Forgot password with no provider: alert the clinic admin(s) via a "System"
message card in Messages + a bell notification (seeded system user + per-clinic
System conversation); clicking deep-links to /settings?tab=careTeam&member=<id>.
Admins can set a member's password directly from the employee dialog
(PATCH /api/staff/:id/password via Better Auth's internal context — no admin
plugin needed).

Patient Portal: "New patient" booking path registers a demographics-only patient
then books; bookings reject double-booked slots (409).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/types/activity.ts

@@ -9,7 +9,8 @@ export type ActivityEntityType =
   | "invoice"
   | "inventory"
   | "dispense"
-  | "task";
+  | "task"
+  | "settings";
 
 export type ActivityEntry = {
   id: string;

backend/src/types/messaging.ts

@@ -25,7 +25,16 @@ export type MessageAttachment =
       mimeType: string;
       size: number;
     }
-  | { kind: "appointment"; appointment: AppointmentSnapshot };
+  | { kind: "appointment"; appointment: AppointmentSnapshot }
+  // A system-generated alert (e.g. an employee asked for a password reset but no
+  // email provider is configured). Rendered as a distinct "System" card that
+  // deep-links an admin to the member's settings.
+  | {
+      kind: "passwordReset";
+      userId: string;
+      userName: string;
+      userEmail: string;
+    };
 
 export type ConversationMessage = {
   id: string;