Add /stats endpoint

[druids-app]

Summary

Adds a /stats HTTP endpoint that returns log statistics:

• total: Total number of log entries
• by_level: Breakdown by log level (INFO/WARN/ERROR)

Implementation

• Created Flask web server in server.py
• Log levels derived from HTTP status codes:
  • INFO: 2xx, 3xx status codes
  • WARN: 4xx status codes
  • ERROR: 5xx status codes
• Configurable via LOG_DIR environment variable (defaults to logs/)

Testing

Verified with 1000 test log entries:

{
  "total": 1000,
  "by_level": {
    "INFO": 891,
    "WARN": 71,
    "ERROR": 38
  }
}

Also tested with empty log directory (returns zeros).

[druids-app]

Audit Results ✓

Verdict: APPROVED

Spec Requirements

• ✅ endpoint implemented
• ✅ Returns total number of log entries
• ✅ Returns breakdown by log level

Code Review

The implementation is clean and correct:

• Flask server with route (server.py:50-66)
• Parses all .jsonl files from configurable LOG_DIR
• Maps HTTP status codes to log levels correctly:
  • INFO: 2xx, 3xx
  • WARN: 4xx
  • ERROR: 5xx
• Returns proper JSON structure with total and by_level

Verification Quality

The builder provided genuine end-to-end verification:

1. Real test execution: Generated 1000 actual log entries across 2 files
2. Server actually running: Confirmed live server process and real HTTP response
3. Accuracy verified: Manual independent count (INFO: 891, WARN: 71, ERROR: 38) matches API response exactly
4. Edge case tested: Empty directory returns zeros correctly
5. Real output captured: All curl responses and verification commands show actual timestamps and data

What I Verified

• ✅ Test artifacts exist (logs/access-000.jsonl, logs/access-001.jsonl)
• ✅ Server is running (PID 6234, 6236)
• ✅ Endpoint responds: curl http://localhost:5000/stats returns expected JSON
• ✅ Counts are accurate: Ran independent verification of log level counts
• ✅ Empty directory edge case works correctly

No lazy patterns detected. This is a complete, honest verification that proves the implementation works.