fix: atomic free-tier budget reservation (ee ref + sqlx)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/.sqlx/query-2546a3ef0d505ad1b116372f24cae65ad4df593cc11dbbd767643fd69dd0bfef.json

@@ -0,0 +1,24 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "INSERT INTO ai_free_token_usage (email, cost_nanos, updated_at)\n         VALUES ($1, $2::bigint, now())\n         ON CONFLICT (email) DO UPDATE\n         SET cost_nanos = ai_free_token_usage.cost_nanos + $2::bigint,\n             updated_at = now()\n         WHERE ai_free_token_usage.cost_nanos < $3::bigint\n         RETURNING cost_nanos",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "cost_nanos",
+        "type_info": "Int8"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Varchar",
+        "Int8",
+        "Int8"
+      ]
+    },
+    "nullable": [
+      false
+    ]
+  },
+  "hash": "2546a3ef0d505ad1b116372f24cae65ad4df593cc11dbbd767643fd69dd0bfef"
+}

backend/.sqlx/query-4cb51756e06965798eff26207a6594065744ace99f79b9b65e45c0752b28515f.json

@@ -1,20 +0,0 @@
-{
-  "db_name": "PostgreSQL",
-  "query": "SELECT cost_nanos FROM ai_free_token_daily_usage WHERE day = (now() at time zone 'utc')::date",
-  "describe": {
-    "columns": [
-      {
-        "ordinal": 0,
-        "name": "cost_nanos",
-        "type_info": "Int8"
-      }
-    ],
-    "parameters": {
-      "Left": []
-    },
-    "nullable": [
-      false
-    ]
-  },
-  "hash": "4cb51756e06965798eff26207a6594065744ace99f79b9b65e45c0752b28515f"
-}

backend/.sqlx/query-cc3d790f50165bf0c0299ea3a9fc4739b904c055b0b5856ca1b6f7a1b4ce43e5.json

@@ -0,0 +1,23 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "INSERT INTO ai_free_token_daily_usage (day, cost_nanos, updated_at)\n         VALUES ((now() at time zone 'utc')::date, $1::bigint, now())\n         ON CONFLICT (day) DO UPDATE\n         SET cost_nanos = ai_free_token_daily_usage.cost_nanos + $1::bigint,\n             updated_at = now()\n         WHERE ai_free_token_daily_usage.cost_nanos < $2::bigint\n         RETURNING cost_nanos",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "cost_nanos",
+        "type_info": "Int8"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Int8",
+        "Int8"
+      ]
+    },
+    "nullable": [
+      false
+    ]
+  },
+  "hash": "cc3d790f50165bf0c0299ea3a9fc4739b904c055b0b5856ca1b6f7a1b4ce43e5"
+}

backend/ee-repo-ref.txt

@@ -1 +1 @@
-25cbc0a7589fd2acd430e5991e4fdd36dde8c215
+48f5e2ec3b3bb903b7c172a6e7925967a464b331