feat: 下游 API 密钥管理 (#103)

* feat: downstream API key usage + proxy log attribution

* chore(schema): regenerate generated artifacts

* test: keep migration replay + platform detection tests stable

* feat: complete downstream api key management validation

* refactor: move downstream keys into console nav

* feat: upgrade downstream keys management console

* feat: harden downstream key management flows

* test: cover downstream key policy guards

* feat: add downstream key grouping and tags

* feat: polish downstream key search and log metadata

* test: fix sqlite migration bootstrap coverage

* perf: isolate vchart bundle loading

* fix: align downstream key drawer metrics

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Co-authored-by: DeliciousBuding <DeliciousBuding@users.noreply.github.com>

src/server/db/generated/postgres.upgrade.sql

@@ -1 +1,2 @@
-ALTER TABLE "model_availability" ADD COLUMN "is_manual" BOOLEAN DEFAULT false;
+ALTER TABLE "downstream_api_keys" ADD COLUMN "group_name" TEXT;
+ALTER TABLE "downstream_api_keys" ADD COLUMN "tags" TEXT;