fix(market): add data staleness detection and API fallback for WebSocket klines

[the-dev-z]

Summary

• Fixes WebSocket data staleness issue where AI makes decisions on outdated data
• Adds automatic API fallback when WebSocket stops updating

Problem (Issue #1028)

Users reported that WebSocket data stops updating but the system continues using stale cached data:

• Two consecutive trading cycles showed identical BTC prices (96307.60)
• All indicators (MACD, RSI) remained unchanged
• AI made decisions based on outdated information

Root Cause

• Kline data was stored without timestamps
• No freshness check before returning cached data
• No fallback mechanism when WebSocket stops working

Solution

1. Added KlineCacheEntry struct to store klines with ReceivedAt timestamp
2. Reduced freshness threshold from 15 minutes to 5 minutes for faster detection
3. Added API fallback: when data is stale, automatically fetch from REST API
4. Added warning logs when stale data is detected

Changes

• market/monitor.go: Added staleness detection and API fallback logic

Test Plan

• Verify kline data includes timestamps after WebSocket updates
• Verify API fallback triggers when data is older than 5 minutes
• Verify warning logs are generated for stale data
• Verify normal operation when WebSocket is working correctly

Fixes #1028

🤖 Generated with Claude Code

[github-actions]

🤖 Advisory Check Results

These are advisory checks to help improve code quality. They won't block your PR from being merged.

📋 PR Information

Title Format: ✅ Good - Follows Conventional Commits
PR Size: 🟢 Small (63 lines: +53 -10)

🔧 Backend Checks

Go Formatting: ⚠️ Needs formatting

Files needing formatting

config/database.go
mcp/client.go
mcp/config.go
mcp/deepseek_client.go
mcp/options.go
mcp/qwen_client.go
mcp/request.go
mcp/request_builder.go
trader/bybit_trader_test.go
trader/lighter_account.go

Go Vet: ✅ Good
Tests: ✅ Passed

Fix locally:

go fmt ./...      # Format code
go vet ./...      # Check for issues
go test ./...     # Run tests

⚛️ Frontend Checks

Build & Type Check: ✅ Success

Fix locally:

cd web
npm run build  # Test build (includes type checking)

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Questions? Feel free to ask in the comments! 🙏

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[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 11 committers have signed the CLA.

✅ tinkle-community
❌ 0xEmberZz
❌ the-dev-z
❌ xqliu
❌ Icyoung
❌ tangmengqiu
❌ ghLcd9dG
❌ MarsDoge
❌ hzb1115
❌ livelybug
❌ Icy

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