## Description
Adds support for sending an ad‑hoc custom notification to the
authenticated user via API and CLI. This is useful for surfacing the
result of scripts or long‑running tasks. Notifications are delivered
through the configured method and the dashboard Inbox, respecting
existing preferences and delivery settings.
## Changes
* New notification template: “Custom Notification” with a label for a
custom title and a custom message.
* New API endpoint: `POST /api/v2/notifications/custom` to send a custom
notification to the requesting user.
* New API endpoint: `GET /notifications/templates/custom` to get custom
notification template.
* New CLI subcommand: `coder notifications custom <title> <message>` to
send a custom notification to the requesting user.
* Documentation updates: Add a “Custom notifications” section under
Administration > Monitoring > Notifications, including instructions on
sending custom notifications and examples of when to use them.
Closes: https://github.com/coder/coder/issues/19611
* Adds `codersdk.ExperimentWebPush` (`web-push`)
* Adds a `coderd/webpush` package that allows sending native push
notifications via `github.com/SherClockHolmes/webpush-go`
* Adds database tables to store push notification subscriptions.
* Adds an API endpoint that allows users to subscribe/unsubscribe, and
send a test notification (404 without experiment, excluded from API docs)
* Adds server CLI command to regenerate VAPID keys (note: regenerating
the VAPID keypair requires deleting all existing subscriptions)
---------
Co-authored-by: Kyle Carberry <kyle@carberry.com>
Change as part of https://github.com/coder/coder/pull/16071
It has been decided that we want to be able to have some notification
templates be disabled _by default_
https://github.com/coder/coder/pull/16071#issuecomment-2580757061.
This adds a new column (`enabled_by_default`) to
`notification_templates` that defaults to `TRUE`. It also modifies the
`inhibit_enqueue_if_disabled` function to reject notifications for
templates that have `enabled_by_default = FALSE` with the user not
explicitly enabling it.