Implement Mastodon 4.5.0 quote notification types

Add support for 'quote' and 'quoted_update' notification types
introduced in Mastodon 4.5.0 (API v7) to improve quote post
interaction tracking.

New notification types:
- 'quote': Notifies when someone quotes your post, showing the
  quote post itself
- 'quoted_update': Notifies when a post you quoted is edited,
  showing your quote post for context

Both types are non-groupable (individual notifications) and
self-quotes don't generate notifications. Existing quote posts
are automatically backfilled with notifications during migration.

Database changes:
- Added 'quote' and 'quoted_update' to notification_type enum
- Added partial index on posts.quote_target_id for performance
- Single migration with explicit COMMIT for enum and backfill

Implementation:
- src/notification.ts: New createQuoteNotification and
  createQuotedUpdateNotifications functions
- src/federation/inbox.ts: Quote notification creation in
  onPostCreated and onPostUpdated handlers
- src/api/v1/notifications.ts, src/api/v2/notifications.ts:
  Added new types to API endpoints
- src/notification.test.ts: 7 test cases covering all scenarios

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: dahlia

CHANGES.md

@@ -97,6 +97,26 @@ To be released.
     URL-encoded form data even when `Content-Type` is missing or set to
     `text/plain`.
 
+ -  Implemented Mastodon 4.5.0 quote notification types (`quote` and
+    `quoted_update`) for improved quote post interaction tracking.
+    Users now receive notifications when their posts are quoted by others
+    and when posts they've quoted are edited by the original authors.
+    Key features include:
+
+     -  Added `quote` notification type that triggers when someone quotes
+        your post, with the notification showing the quote post itself.
+     -  Added `quoted_update` notification type that triggers when a post
+        you quoted is edited, with the notification showing your quote post
+        to provide context.
+     -  Both notification types are non-groupable, meaning each quote or edit
+        generates an individual notification for better visibility.
+     -  Self-quotes (quoting your own posts) do not generate notifications
+        to avoid unnecessary noise.
+     -  Existing quote posts are automatically backfilled with notifications
+        during migration to ensure consistent notification history.
+     -  Added database index on `posts.quote_target_id` for improved query
+        performance when looking up quote relationships.
+
 [#94]: https://github.com/fedify-dev/hollo/issues/94
 [#312]: https://github.com/fedify-dev/hollo/issues/312
 [#170]: https://github.com/fedify-dev/hollo/issues/170

drizzle/0076_fair_frank_castle.sql

@@ -0,0 +1,39 @@
+ALTER TYPE "public"."notification_type" ADD VALUE 'quote';--> statement-breakpoint
+ALTER TYPE "public"."notification_type" ADD VALUE 'quoted_update';--> statement-breakpoint
+COMMIT;--> statement-breakpoint
+
+-- Backfill notifications for existing quote posts
+INSERT INTO notifications (id, account_owner_id, type, actor_account_id, target_post_id, group_key, created)
+SELECT
+  gen_random_uuid(),
+  ao.id as account_owner_id,
+  'quote'::notification_type as type,
+  p.actor_id as actor_account_id,
+  p.id as target_post_id,
+  'ungrouped:' || gen_random_uuid() as group_key,
+  p.published as created
+FROM posts p
+INNER JOIN posts target ON p.quote_target_id = target.id
+INNER JOIN accounts target_account ON target.actor_id = target_account.id
+INNER JOIN account_owners ao ON target_account.id = ao.id
+WHERE p.quote_target_id IS NOT NULL
+  AND p.actor_id != target.actor_id  -- Exclude self-quotes
+ON CONFLICT DO NOTHING;--> statement-breakpoint
+
+-- Create notification groups for backfilled quote notifications
+INSERT INTO notification_groups (group_key, account_owner_id, type, notifications_count, most_recent_notification_id, sample_account_ids)
+SELECT DISTINCT
+  n.group_key,
+  n.account_owner_id,
+  'quote'::notification_type,
+  1,
+  n.id,
+  ARRAY[n.actor_account_id]
+FROM notifications n
+WHERE n.type = 'quote'
+  AND NOT EXISTS (
+    SELECT 1 FROM notification_groups ng WHERE ng.group_key = n.group_key
+  )
+ON CONFLICT DO NOTHING;--> statement-breakpoint
+
+CREATE INDEX "posts_quote_target_id_index" ON "posts" USING btree ("quote_target_id") WHERE "posts"."quote_target_id" is not null;