feat: implement Epic 0 - Project Setup & Foundation

Implemented all 5 stories from Epic 0:

Story 0.1: Project Initialization
- Initialize Go module with path git.dcentral.systems/toolz/goplt
- Create complete directory structure (cmd/, internal/, pkg/, modules/, config/, etc.)
- Add comprehensive .gitignore for Go projects
- Create README.md with project overview and setup instructions

Story 0.2: Configuration Management System
- Define ConfigProvider interface in pkg/config
- Implement Viper-based configuration in internal/config
- Create configuration loader with environment support
- Add default, development, and production YAML config files

Story 0.3: Structured Logging System
- Define Logger interface in pkg/logger
- Implement Zap-based logger in internal/logger
- Add request ID middleware for Gin
- Create global logger export with convenience functions
- Support context-aware logging with request/user ID extraction

Story 0.4: CI/CD Pipeline
- Create GitHub Actions workflow for CI (test, lint, build, fmt)
- Add comprehensive Makefile with development commands
- Configure golangci-lint with reasonable defaults

Story 0.5: Dependency Injection and Bootstrap
- Create FX-based DI container in internal/di
- Implement provider functions for Config and Logger
- Create application entry point in cmd/platform/main.go
- Add lifecycle management with graceful shutdown

All acceptance criteria met:
- go build ./cmd/platform succeeds
- go test ./... runs successfully
- go mod verify passes
- Config loads from config/default.yaml
- Logger can be injected and used
- Application starts and shuts down gracefully

pkg/logger/global.go

@@ -0,0 +1,60 @@
+package logger
+
+import (
+	"context"
+	"sync"
+)
+
+var (
+	globalLogger Logger
+	globalMu     sync.RWMutex
+)
+
+// SetGlobalLogger sets the global logger instance.
+func SetGlobalLogger(l Logger) {
+	globalMu.Lock()
+	defer globalMu.Unlock()
+	globalLogger = l
+}
+
+// GetGlobalLogger returns the global logger instance.
+// Returns a no-op logger if no global logger is set.
+func GetGlobalLogger() Logger {
+	globalMu.RLock()
+	defer globalMu.RUnlock()
+	if globalLogger == nil {
+		return &noOpLogger{}
+	}
+	return globalLogger
+}
+
+// Debug logs a message at debug level using the global logger.
+func Debug(msg string, fields ...Field) {
+	GetGlobalLogger().Debug(msg, fields...)
+}
+
+// Info logs a message at info level using the global logger.
+func Info(msg string, fields ...Field) {
+	GetGlobalLogger().Info(msg, fields...)
+}
+
+// Warn logs a message at warning level using the global logger.
+func Warn(msg string, fields ...Field) {
+	GetGlobalLogger().Warn(msg, fields...)
+}
+
+// ErrorLog logs a message at error level using the global logger.
+func ErrorLog(msg string, fields ...Field) {
+	GetGlobalLogger().Error(msg, fields...)
+}
+
+// noOpLogger is a logger that does nothing.
+// Used as a fallback when no global logger is set.
+type noOpLogger struct{}
+
+func (n *noOpLogger) Debug(msg string, fields ...Field) {}
+func (n *noOpLogger) Info(msg string, fields ...Field)  {}
+func (n *noOpLogger) Warn(msg string, fields ...Field)  {}
+func (n *noOpLogger) Error(msg string, fields ...Field) {}
+func (n *noOpLogger) With(fields ...Field) Logger        { return n }
+func (n *noOpLogger) WithContext(ctx context.Context) Logger { return n }