fix: update tracing subscriber to write JSON output to stderr

[eleanorjboyd]

What broke: The commit added performance tracing/logging code. The new code was using a library called tracing-subscriber which, by default, writes log messages to stdout. This corrupted the JSONRPC protocol, causing the "Connection Error" and endless loading.

Fix: tracing library to write to stderr (standard error) instead of stdout.

resolves: #341

[github-actions]

Test Coverage Report (Linux)

Metric	Value
Current Coverage	57.6%
Base Branch Coverage	57.6%
Delta	0% ➖

---

Coverage unchanged.

[github-actions]

Performance Report (Linux) 🚀

Metric	PR	Baseline	Delta	Change
Server Startup	1ms	1ms	0ms	0%
Full Refresh	364ms	520ms	-156ms	-30.0%

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[github-actions]

Performance Report (Windows) ⚠️

Metric	PR	Baseline	Delta	Change
Server Startup	17ms	15ms	2ms	13.3%
Full Refresh	2975ms	2079ms	896ms	43.1%

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)

[github-actions]

Test Coverage Report (Windows)

Metric	Value
Current Coverage	54.15%
Base Branch Coverage	54.15%
Delta	0% ➖

---

Coverage unchanged.

[github-actions]

Performance Report (macOS)

Metric	PR	Baseline	Delta
Server Startup	869ms	1239ms	-370ms
Full Refresh	48466ms	71109ms	-22643ms

---

Legend

• 🚀 Significant speedup (>100ms faster)
• ✅ Faster than baseline
• ➖ No significant change
• 🔺 Slower than baseline (>100ms)
• ⚠️ Significant slowdown (>500ms)