fix: 恢复所有迁移文件以修复校验和错误

恢复了以下迁移文件到原始状态：
- 004_add_redeem_code_notes.sql
- 005_schema_parity.sql
- 006_fix_invalid_subscription_expires_at.sql
- 007_add_user_allowed_groups.sql
- 008_seed_default_group.sql
- 009_fix_usage_logs_cache_columns.sql
- 010_add_usage_logs_aggregated_indexes.sql
- 011_remove_duplicate_unique_indexes.sql
- 012_add_user_subscription_soft_delete.sql
- 013_log_orphan_allowed_groups.sql
- 014_drop_legacy_allowed_groups.sql
- 015_fix_settings_unique_constraint.sql
- 016_soft_delete_partial_unique_indexes.sql
- 018_user_attributes.sql
- 019_migrate_wechat_to_attributes.sql
- 024_add_gemini_tier_id.sql

数据库迁移文件不应在应用后修改，即使只是注释。

backend/migrations/024_add_gemini_tier_id.sql

@@ -1,30 +1,30 @@
--- +goose Up
--- +goose StatementBegin
--- 为 Gemini Code Assist OAuth 账号添加默认 tier_id
--- 包括显式标记为 code_assist 的账号，以及 legacy 账号（oauth_type 为空但 project_id 存在）
-UPDATE accounts
-SET credentials = jsonb_set(
-    credentials,
-    '{tier_id}',
-    '"LEGACY"',
-    true
-)
-WHERE platform = 'gemini'
-  AND type = 'oauth'
-  AND jsonb_typeof(credentials) = 'object'
-  AND credentials->>'tier_id' IS NULL
-  AND (
-    credentials->>'oauth_type' = 'code_assist'
-    OR (credentials->>'oauth_type' IS NULL AND credentials->>'project_id' IS NOT NULL)
-  );
--- +goose StatementEnd
-
--- +goose Down
--- +goose StatementBegin
--- 回滚：删除 tier_id 字段
-UPDATE accounts
-SET credentials = credentials - 'tier_id'
-WHERE platform = 'gemini'
-  AND type = 'oauth'
-  AND credentials ? 'tier_id';
--- +goose StatementEnd
+-- +goose Up
+-- +goose StatementBegin
+-- 为 Gemini Code Assist OAuth 账号添加默认 tier_id
+-- 包括显式标记为 code_assist 的账号，以及 legacy 账号（oauth_type 为空但 project_id 存在）
+UPDATE accounts
+SET credentials = jsonb_set(
+    credentials,
+    '{tier_id}',
+    '"LEGACY"',
+    true
+)
+WHERE platform = 'gemini'
+  AND type = 'oauth'
+  AND jsonb_typeof(credentials) = 'object'
+  AND credentials->>'tier_id' IS NULL
+  AND (
+    credentials->>'oauth_type' = 'code_assist'
+    OR (credentials->>'oauth_type' IS NULL AND credentials->>'project_id' IS NOT NULL)
+  );
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+-- 回滚：删除 tier_id 字段
+UPDATE accounts
+SET credentials = credentials - 'tier_id'
+WHERE platform = 'gemini'
+  AND type = 'oauth'
+  AND credentials ? 'tier_id';
+-- +goose StatementEnd