db: drizzle schema matching spec 02, initial migrations, settings service

Migration 0000 enables citext; 0001 creates all 39 tables. DB tests use a
throwaway database per file (TEST_DATABASE_URL, derived from .env in dev,
a postgres service in CI). Decision 0002: pg driver and @fastify/cookie.

Task: M1-T1

apps/api/src/db/migrations/meta/0000_snapshot.json

@@ -0,0 +1,18 @@
+{
+  "id": "2346704b-51cc-4251-9e70-f9e166bd89b8",
+  "prevId": "00000000-0000-0000-0000-000000000000",
+  "version": "7",
+  "dialect": "postgresql",
+  "tables": {},
+  "enums": {},
+  "schemas": {},
+  "views": {},
+  "sequences": {},
+  "roles": {},
+  "policies": {},
+  "_meta": {
+    "columns": {},
+    "schemas": {},
+    "tables": {}
+  }
+}

apps/api/src/db/migrations/meta/_journal.json

@@ -0,0 +1,20 @@
+{
+  "version": "7",
+  "dialect": "postgresql",
+  "entries": [
+    {
+      "idx": 0,
+      "version": "7",
+      "when": 1792267218726,
+      "tag": "0000_citext",
+      "breakpoints": true
+    },
+    {
+      "idx": 1,
+      "version": "7",
+      "when": 1792267225335,
+      "tag": "0001_initial",
+      "breakpoints": true
+    }
+  ]
+}