Enable notification support for the chat messages

[vikasbolla]

Backend

New event types (models/events.go)

CHAT_USER_MESSAGE — fired when a user sends a chat message, notifies admin
CHAT_ADMIN_REPLY — fired when admin replies, notifies the user
Chat notification logic (services/chat.go)

• Admin rate-limit: email is suppressed if an admin has already replied to the conversation within the last 6 hours (HasAdminRepliedSince) — prevents inbox spam on active conversations
• Unread count: when no admin reply exists, counts unanswered user messages (GetUnreadUserMessageCount) and includes the count in the email body so admin can gauge urgency — "There are 3 unread messages from user X"
• User notification: no rate-limit — every admin reply triggers an email since the user may not be watching the UI
• Both goroutines use a bounded context.WithTimeout (30s / 15s) to prevent goroutine leaks on a hung DB

New DB methods (db/interface.go, db/mongodb/chat.go)

HasAdminRepliedSince(ctx, userID, convID, since) — single CountDocuments on sender=admin AND timestamp > since
GetUnreadUserMessageCount(ctx, userID, convID) — counts user messages after the most recent admin message timestamp; returns total if admin has never replied

SendGrid fixes (notifier/client/mail/mail.go)

• Fixed HTTP 400: admin-only events (NotifyAdmin=true, Notify=false) now use AddTos instead of AddBCCs — SendGrid rejects BCC-only messages

• Fixed content-type: "text" → "text/plain"

• Notify() now returns an error on non-202 responses instead of ignoring it

• MarkEventAsNotified is now only called when Notify succeeds — failed sends are retried on the next poll cycle instead of being permanently lost

Frontend

Timestamp display (components/ChatSupport.jsx, components/ChatAdmin.jsx)

• Messages from today show time only: 02:45 PM
• Messages from earlier this year show date + time: Jun 12, 02:45 PM
• Messages from a previous year show full date: Jun 12, 2024, 02:45 PM

How it works end-to-end

• User sends a message → notifyAdminOfUserMessage goroutine fires → writes CHAT_USER_MESSAGE event to MongoDB
• Event-notifier binary picks it up via tailable cursor → calls SendGrid → emails PowerACL@ibm.com
• Admin replies → notifyUserOfAdminReply goroutine fires → writes CHAT_ADMIN_REPLY event
• Event-notifier resolves user email from Keycloak → emails the user