Replaces routine use of `scripts/seed-router-config.ts` and
`scripts/seed-streaming-tts.ts` with `POST /api/admin/config/router`.
Operators can now patch one provider at a time without shelling into
the Railway runner; the seed scripts stay as break-glass tools for
cold-boot and disaster recovery.
The endpoint accepts a discriminated-union slice list (openrouter /
azure / dashscope-cosyvoice / streaming-tts), envelope-encrypts
plaintext keys in-process (never echoed back), and supports
merge/reset modes plus dryRun. Writes go through the existing
configKV + Redis `configkv:invalidate` channel so multi-instance
deployments pick up changes within the pub/sub propagation window.
Guarded by the existing `authGuard + adminGuard` pair
(`ADMIN_EMAILS` allowlist + verified email).
RainbowBird
c1b88701db