add auth

migrations/0004_create_auth_tokens.up.sql

@@ -0,0 +1,28 @@
+-- One-shot tokens used by the forgot-password and email-verification flows.
+--
+-- We never store the raw token; only the SHA-256 hash. The plaintext lives
+-- only in the email link. This means a DB leak can't be replayed against the
+-- live flow.
+--
+-- `purpose` discriminates the two flows so we can keep one narrow table:
+--   'password_reset'      → expires in ~1h
+--   'email_verification'  → expires in ~24h
+--
+-- `used_at` is set the first time a token is consumed. The handler must check
+-- both `used_at IS NULL` AND `expires_at > now()` before honouring a token.
+CREATE TABLE IF NOT EXISTS auth_tokens (
+    id          UUID         PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id     UUID         NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    purpose     VARCHAR(32)  NOT NULL,
+    token_hash  CHAR(64)     NOT NULL UNIQUE,
+    expires_at  TIMESTAMPTZ  NOT NULL,
+    used_at     TIMESTAMPTZ,
+    created_at  TIMESTAMPTZ  NOT NULL DEFAULT now(),
+    CHECK (purpose IN ('password_reset', 'email_verification'))
+);
+
+CREATE INDEX IF NOT EXISTS auth_tokens_user_purpose_idx
+    ON auth_tokens (user_id, purpose);
+
+CREATE INDEX IF NOT EXISTS auth_tokens_expires_at_idx
+    ON auth_tokens (expires_at);