[www] password/email recovery (#146)

* pw/email recovery

* fix migration

apps/auth/migrations/0015_rate_limit.sql

@@ -0,0 +1,11 @@
+-- Fixed-window counters: "at most N of these per key per window". What caps the emails
+-- this server sends — password-recovery codes (`auth`) and email-change codes (`accounts`)
+-- — per target account and per requesting IP, so a mailbox can't be flooded by anyone who
+-- knows its address. Mirrored by RATE_LIMIT_SCHEMA_DDL in @repo/domain's rate-limit-db.ts,
+-- which says how a key is taken and when rows are purged.
+
+CREATE TABLE IF NOT EXISTS rate_limit (
+  key TEXT PRIMARY KEY,
+  window_started_at INTEGER NOT NULL,
+  count INTEGER NOT NULL
+);