feat(logging): implement configurable log levels via VITE_LOG_LEVEL

Add comprehensive logging configuration system with environment variable support.
Environment files now include appropriate log levels per build mode:
- Development: debug (maximum visibility)
- Production: warn (minimal noise)
- Testing: info (balanced output)

Includes smart default behavior based on platform and environment,
enhanced logger methods for level checking, and comprehensive documentation.
All existing logging calls remain backward compatible.

Closes logging configuration request

README.md

@@ -51,6 +51,35 @@ See [BUILDING.md](BUILDING.md) for comprehensive build instructions for all plat
 
 TimeSafari provides a simple script-based approach to clear the database for development purposes.
 
+## Logging Configuration
+
+TimeSafari supports configurable logging levels via the `VITE_LOG_LEVEL` environment variable. This allows developers to control console output verbosity without modifying code.
+
+### Quick Usage
+
+```bash
+# Show only errors
+VITE_LOG_LEVEL=error npm run dev
+
+# Show warnings and errors
+VITE_LOG_LEVEL=warn npm run dev
+
+# Show info, warnings, and errors (default)
+VITE_LOG_LEVEL=info npm run dev
+
+# Show all log levels including debug
+VITE_LOG_LEVEL=debug npm run dev
+```
+
+### Available Levels
+
+- **`error`**: Critical errors only
+- **`warn`**: Warnings and errors (default for production web)
+- **`info`**: Info, warnings, and errors (default for development/capacitor)
+- **`debug`**: All log levels including verbose debugging
+
+See [Logging Configuration Guide](doc/logging-configuration.md) for complete details.
+
 ### Quick Usage
 ```bash
 # Run the database clearing script