feat: complete Phase 0 Enterprise IAM

src/db/migrations/postgres/0002_create_users.sql

@@ -0,0 +1,16 @@
+CREATE TABLE IF NOT EXISTS users (
+    id              TEXT    PRIMARY KEY NOT NULL,
+    tenant_id       TEXT    NOT NULL REFERENCES tenants(id) ON DELETE RESTRICT,
+    username        TEXT    NOT NULL,
+    password_hash   TEXT    NOT NULL,
+    -- 1 = active, 2 = disabled, 3 = locked
+    status          INTEGER NOT NULL DEFAULT 1,
+    last_login_at   TEXT,
+    created_at      TEXT    NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
+    updated_at      TEXT    NOT NULL DEFAULT (strftime('%Y-%m-%dT%H:%M:%SZ', 'now')),
+    UNIQUE (tenant_id, username)
+);
+
+CREATE INDEX IF NOT EXISTS idx_users_username  ON users(username);
+CREATE INDEX IF NOT EXISTS idx_users_tenant_id ON users(tenant_id);
+CREATE INDEX IF NOT EXISTS idx_users_status    ON users(status);