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/config/config.go

@@ -0,0 +1,39 @@
+package config
+
+import "time"
+
+// ConfigProvider defines the interface for configuration management.
+// It provides type-safe access to configuration values from various sources
+// (YAML files, environment variables, etc.).
+type ConfigProvider interface {
+	// Get retrieves a configuration value by key.
+	// Returns nil if the key is not found.
+	Get(key string) any
+
+	// Unmarshal unmarshals the entire configuration into the provided struct.
+	// The struct should use appropriate tags for mapping configuration keys.
+	Unmarshal(v any) error
+
+	// GetString retrieves a string value by key.
+	// Returns empty string if the key is not found.
+	GetString(key string) string
+
+	// GetInt retrieves an integer value by key.
+	// Returns 0 if the key is not found or cannot be converted.
+	GetInt(key string) int
+
+	// GetBool retrieves a boolean value by key.
+	// Returns false if the key is not found or cannot be converted.
+	GetBool(key string) bool
+
+	// GetStringSlice retrieves a string slice value by key.
+	// Returns nil if the key is not found.
+	GetStringSlice(key string) []string
+
+	// GetDuration retrieves a duration value by key.
+	// Returns 0 if the key is not found or cannot be parsed.
+	GetDuration(key string) time.Duration
+
+	// IsSet checks if a configuration key is set.
+	IsSet(key string) bool
+}