fix: prevent DeepSeek token overflow with product-level limits (#1431)

* feat: enforce strategy limits to prevent token overflow

* fix: tune token limits after real-world testing

- Relax kline max 20→30, timeframes 3→4 (tested ~41K tokens, safe under 131K)
- Restore ranking limits to original [5,10,15,20] options (only ~1.5K token impact)
- Add static coins limit (max 3) with toast notification
- Add timeframe limit toast when exceeding 4
- Log SSE token usage (prompt/completion/total) from API response
- Fix nil logger crash in claw402 data client (engine.go)

* feat: add token estimation functionality for strategy configurations

* feat: add discard changes button in Strategy Studio for unsaved modifications

* feat: retain selected strategy after saving in Strategy Studio

* feat: enhance strategy display in Strategy Studio with improved layout and sorting of token limits

* refactor: improve layout and styling of stats display in CompetitionPage

* refactor: replace select elements with NofxSelect component for improved consistency in strategy configuration forms

* style: update NofxSelect component to use smaller text size for improved readability

* feat: implement token overflow handling in strategy updates and UI

---------

Co-authored-by: Dean <afei.wuhao@gmail.com>

mcp/client.go

@@ -760,10 +760,21 @@ func ParseSSEStream(body io.Reader, onChunk func(string), onLine func()) (string
 				} `json:"delta"`
 				FinishReason *string `json:"finish_reason"`
 			} `json:"choices"`
+			Usage *struct {
+				PromptTokens     int `json:"prompt_tokens"`
+				CompletionTokens int `json:"completion_tokens"`
+				TotalTokens      int `json:"total_tokens"`
+			} `json:"usage,omitempty"`
 		}
 		if err := json.Unmarshal([]byte(data), &chunk); err != nil {
 			continue // skip malformed chunks
 		}
+
+		if chunk.Usage != nil && chunk.Usage.TotalTokens > 0 {
+			fmt.Printf("📊 [TokenUsage] prompt=%d, completion=%d, total=%d\n",
+				chunk.Usage.PromptTokens, chunk.Usage.CompletionTokens, chunk.Usage.TotalTokens)
+		}
+
 		if len(chunk.Choices) == 0 {
 			continue
 		}