Align code default for LOG_LEVEL with docs

[ccreighton-apptio]

🐛 Bug-fix PR

Before opening this PR please:

1. make lint - passes ruff, mypy, pylint
2. make test - all unit + integration tests green
3. make coverage - ≥ 80 %
4. make docker docker-run-ssl or make podman podman-run-ssl
5. Update relevant documentation.
6. Tested with sqlite and postgres + redis.
7. Manual regression no longer fails. Ensure the UI and /version work correctly.

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📌 Summary

What problem does this PR fix and why?

The docs state that INFO is the default log level, but ERROR is used here.

🔁 Reproduction Steps

Link the issue and minimal steps to reproduce the bug.

1. Don't set LOG_LEVEL, observe logs
2. Set LOG_LEVEL=INFO, observe logs

Expected: No change

Actual: INFO logs now present

🐞 Root Cause

What was wrong and where?

The documentation states that the default level is different than what is actually applied

💡 Fix Description

How did you solve it? Key design points.

The documented default is now applied

🧪 Verification

Check	Command	Status
Lint suite	make lint
Unit tests	make test
Coverage ≥ 80 %	make coverage
Manual regression no longer fails	steps / screenshots

📐 MCP Compliance (if relevant)

• Matches current MCP spec
• No breaking change to MCP clients

✅ Checklist

• Code formatted (make black isort pre-commit)
• No secrets/credentials committed