fix(adaptive): 修复 429 计数归零写入及 reset 语义

- sql.rs: UPDATE 时对 concurrent_429_count / rpm_429_count 加 COALESCE(, 0)，避免 None 覆写为 NULL
- effects.rs: rpm_429_count 始终写入 Some(projection.rpm_429_count)，不再过滤零值；新增 unknown-429 场景下零值持久化的单元测试
- adaptive.rs: reset 接口将两个计数字段置为 Some(0) 而非 None，与数据库默认语义对齐；同步修正集成测试断言
- docker-compose.build.yml: 补充 AETHER_GATEWAY_AUTO_PREPARE_DATABASE 默认开启
- README.md: 同步说明 build compose 也已默认开启自动迁移

crates/aether-data/src/repository/provider_catalog/sql.rs

@@ -1738,8 +1738,8 @@ SET
   END,
   oauth_invalid_reason = $26,
   status_snapshot = $27,
-  concurrent_429_count = $28,
-  rpm_429_count = $29,
+  concurrent_429_count = COALESCE($28, 0),
+  rpm_429_count = COALESCE($29, 0),
   last_429_at = CASE
     WHEN $30::double precision IS NULL THEN NULL
     ELSE TO_TIMESTAMP($30::double precision)