Rename shared/logging/ to shared/log_config/ to avoid stdlib shadow

shared/logging/ shadows Python's stdlib logging module, causing a
circular import when any code does `import logging`. This breaks
both the entrypoint Redis flush and Hypercorn app loading.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

log_config/__init__.py

@@ -0,0 +1,3 @@
+from .setup import configure_logging, get_logger
+
+__all__ = ["configure_logging", "get_logger"]

log_config/setup.py

@@ -0,0 +1,66 @@
+"""
+Structured JSON logging for all Rose Ash apps.
+
+Call configure_logging(app_name) once at app startup.
+Use get_logger(name) anywhere to get a logger that outputs JSON to stdout.
+"""
+from __future__ import annotations
+
+import json
+import logging
+import sys
+from datetime import datetime, timezone
+
+
+class JSONFormatter(logging.Formatter):
+    """Format log records as single-line JSON objects."""
+
+    def __init__(self, app_name: str = ""):
+        super().__init__()
+        self.app_name = app_name
+
+    def format(self, record: logging.LogRecord) -> str:
+        entry = {
+            "timestamp": datetime.now(timezone.utc).isoformat(),
+            "level": record.levelname,
+            "app": self.app_name,
+            "logger": record.name,
+            "message": record.getMessage(),
+        }
+        # Include extra fields if set on the record
+        for key in ("event_type", "user_id", "request_id", "duration_ms"):
+            val = getattr(record, key, None)
+            if val is not None:
+                entry[key] = val
+
+        if record.exc_info and record.exc_info[0] is not None:
+            entry["exception"] = self.formatException(record.exc_info)
+
+        return json.dumps(entry, default=str)
+
+
+_configured = False
+
+
+def configure_logging(app_name: str, level: int = logging.INFO) -> None:
+    """Set up structured JSON logging to stdout. Safe to call multiple times."""
+    global _configured
+    if _configured:
+        return
+    _configured = True
+
+    handler = logging.StreamHandler(sys.stdout)
+    handler.setFormatter(JSONFormatter(app_name=app_name))
+
+    root = logging.getLogger()
+    root.setLevel(level)
+    root.addHandler(handler)
+
+    # Quiet down noisy libraries
+    for name in ("httpx", "httpcore", "asyncio", "sqlalchemy.engine"):
+        logging.getLogger(name).setLevel(logging.WARNING)
+
+
+def get_logger(name: str) -> logging.Logger:
+    """Get a named logger. Uses the structured JSON format once configure_logging is called."""
+    return logging.getLogger(name)