Enhance build system and logging configuration

- Add scripts/build.sh to compile binaries into bin/ directory

- Move all zerolog setup logic from cmd/server/main.go to pkg/config

- Add log level configuration support (trace, debug, info, warn, error, fatal, panic)

- Simplify cmd/server/main.go from 57 to 27 lines (53% reduction)

- Update .gitignore to use bin/ directory instead of individual files

- Document build process and bin directory in AGENTS.md

- Maintain backward compatibility with all existing functionality

config.example.yaml

@@ -21,6 +21,10 @@ logging:
   # Enable JSON output for structured logging (default: false)
   # When true, logs are output in JSON format instead of console format
   json: false
+  
+  # Log level (default: "trace")
+  # Options: "trace", "debug", "info", "warn", "error", "fatal", "panic"
+  level: trace
 
 # Telemetry configuration (OpenTelemetry)
 telemetry:
@@ -53,6 +57,7 @@ telemetry:
 # DLC_SERVER_PORT=8080
 # DLC_SHUTDOWN_TIMEOUT=30s
 # DLC_LOGGING_JSON=false
+# DLC_LOGGING_LEVEL=trace
 # DLC_TELEMETRY_ENABLED=true
 # DLC_TELEMETRY_OTLP_ENDPOINT="jaeger:4317"
 # DLC_TELEMETRY_SERVICE_NAME="DanceLessonsCoach"