Offers, redemption, preview subscriptions (#4121)

* Initial db migration/impl, guarded partner routes

* Add guard to /redeem

* Add `public` column to products prices, only expose public prices

* Query cache

* Add partner subscription type

* 5 days subscription interval, metadata

* Create server on redeem

* Query cache

* Fix race condition

* Unprovision Medal subscriptions

* Consider due expiring charge as unprovisionable

* Query cache

* Use a queue

* Promote to full subscription, fmt + clippy

* Patch expiring charge on promotion, comments

* Additional comments

* Add `tags` field to Archon /create request

* Address review comments

* Query cache

* Final fixes to edit_subscription

* Appease clippy

* fmt

apps/labrinth/migrations/20250804221014_users-redeemals.sql

@@ -0,0 +1,9 @@
+CREATE TABLE users_redeemals (
+    id            SERIAL PRIMARY KEY,
+    user_id       BIGINT NOT NULL REFERENCES users(id),
+    offer         VARCHAR NOT NULL,
+    redeemed      TIMESTAMP WITH TIME ZONE NOT NULL,
+    status        VARCHAR NOT NULL,
+    last_attempt  TIMESTAMP WITH TIME ZONE,
+    n_attempts    INTEGER NOT NULL
+);

apps/labrinth/migrations/20250805001654_product-prices-public.sql

@@ -0,0 +1,4 @@
+ALTER TABLE
+  products_prices
+ADD COLUMN
+  public BOOLEAN NOT NULL DEFAULT true;