docs: 更新协议文档，删除废弃计划文档

- 更新 http-error-codes, user-points-chat-data-protocol
- 更新 divination-run-protocol, profile-protocol
- 删除废弃的后端和前端设计计划文档

docs/protocols/common/user-points-chat-data-protocol.md

@@ -28,7 +28,7 @@ Protocol verification status:
 - Charge timing: deduct after worker run succeeds (`RUN_FINISHED` path).
 - Failure behavior: failed/canceled runs do not deduct points.
 - Precheck: before accepting a run, backend must verify `available = balance - frozen_balance >= 20`.
-- Session follow-up cap: one session allows at most 4 user runs total (initial divination + 3 follow-ups).
+- Session follow-up cap: one session allows at most 2 user runs total (initial divination + 1 follow-up).
 - Billing idempotency key for per-run consume: `chat.run.success:{session_id}:{run_id}`.
 
 ## Table contract