[DO NOT MERGE] Email notification system (#4338)

* Migration

* Fixup db models

* Redis

* Stuff

* Switch PKs to BIGSERIALs, insert to notifications_deliveries when inserting notifications

* Queue, templates

* Query cache

* Fixes, fixtures

* Perf, cache template data & HTML bodies

* Notification type configuration, ResetPassword notification type

* Reset password

* Query cache

* Clippy + fmt

* Traces, fix typo, fix user email in ResetPassword

* send_email

* Models, db

* Remove dead code, adjust notification settings in migration

* Clippy fmt

* Delete dead code, fixes

* Fmt

* Update apps/labrinth/src/queue/email.rs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>

* Remove old fixtures

* Unify email retry delay

* Fix type

* External notifications

* Remove `notifications_types_preference_restrictions`, as user notification preferences is out of scope for this PR

* Query cache, fmt, clippy

* Fix join in get_many_user_exposed_on_site

* Remove migration comment

* Query cache

* Update html body urls

* Remove comment

* Add paymentfailed.service variable to PaymentFailed notification variant

* Fix compile error

* Fix deleting notifications

* Update apps/labrinth/src/database/models/user_item.rs

Co-authored-by: Josiah Glosson <soujournme@gmail.com>
Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>

* Update apps/labrinth/src/database/models/user_item.rs

Co-authored-by: Josiah Glosson <soujournme@gmail.com>
Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>

* Update Cargo.toml

Co-authored-by: Josiah Glosson <soujournme@gmail.com>
Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>

* Update apps/labrinth/migrations/20250902133943_notification-extension.sql

Co-authored-by: Josiah Glosson <soujournme@gmail.com>
Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>

* Address review comments

* Fix compliation

* Update apps/labrinth/src/database/models/users_notifications_preferences_item.rs

Co-authored-by: Josiah Glosson <soujournme@gmail.com>
Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>

* Use strfmt to format emails

* Configurable Reply-To

* Configurable Reply-To

* Refactor for email background task

* Send some emails inline

* Fix account creation email check

* Revert "Use strfmt to format emails"

This reverts commit e0d6614afe.

* Reintroduce fill_template

* Set password reset email inline

* Process more emails per index

* clippy fmt

* Query cache

---------

Signed-off-by: François-Xavier Talbot <108630700+fetchfern@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Josiah Glosson <soujournme@gmail.com>

apps/labrinth/.sqlx/query-a92900cba0e27410d29910c991b9a161ef58e39455454e5b3a380ed62eb15eb2.json

@@ -0,0 +1,18 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n            UPDATE notifications_deliveries\n            SET\n              delivery_priority = $2,\n              status = $3,\n              next_attempt = $4,\n              attempt_count = $5\n            WHERE id = $1\n            ",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Int8",
+        "Int4",
+        "Varchar",
+        "Timestamptz",
+        "Int4"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "a92900cba0e27410d29910c991b9a161ef58e39455454e5b3a380ed62eb15eb2"
+}