♲ Refactor configuration to use viper with context propagation

- Replace global ConfigPath and Overrides with viper-based configuration
- Add viper.New() to create configurable viper instances
- Store viper and unmarshaled Config struct in context for testability
- Add RetrieveFromContext and AddToContext helper functions
- Update files.Append to accept context and retrieve config from it
- Update formatters.Preferred and formatters.New to accept context
- Add PersistentPreRunE in CLI to create and configure viper instance
- Support -c flag for custom config file path
- Support -v flag for config value overrides
- Update all test files to create viper and add to context
- Remove unused config types and load functions
- Add viper as dependency with automatic env var support (MYLOG_*)

formatters/null_test.go

@@ -1,44 +1,59 @@
 package formatters
 
 import (
+	"context"
 	"testing"
 	"time"
 
+	"codeberg.org/danjones000/my-log/config"
 	"codeberg.org/danjones000/my-log/models"
 	"github.com/nalgeon/be"
+	"github.com/spf13/viper"
 )
 
 var empty []byte
 
+func setupNullTestContext(t *testing.T) context.Context {
+	t.Helper()
+	v := viper.New()
+	v.SetConfigType("toml")
+	return config.AddToContext(t.Context(), v)
+}
+
 func TestNullName(t *testing.T) {
-	f, err := New("zero")
+	ctx := setupNullTestContext(t)
+	f, err := New(ctx, "zero")
 	be.Err(t, err, nil)
 	be.Equal(t, f.Name(), "zero")
 }
 
 func TestNullMeta(t *testing.T) {
-	f, _ := New("zero")
+	ctx := setupNullTestContext(t)
+	f, _ := New(ctx, "zero")
 	o, err := f.Meta(models.Meta{Key: "foo", Value: 42})
 	be.Err(t, err, nil)
 	be.Equal(t, o, empty)
 }
 
 func TestNullEntry(t *testing.T) {
-	f, _ := New("zero")
+	ctx := setupNullTestContext(t)
+	f, _ := New(ctx, "zero")
 	o, err := f.Entry(models.Entry{Title: "title", Date: time.Now()})
 	be.Err(t, err, nil)
 	be.Equal(t, o, empty)
 }
 
 func TestNullLog(t *testing.T) {
-	f, _ := New("zero")
+	ctx := setupNullTestContext(t)
+	f, _ := New(ctx, "zero")
 	o, err := f.Log(models.Log{Name: "jim", Entries: []models.Entry{{Title: "title", Date: time.Now()}}})
 	be.Err(t, err, nil)
 	be.Equal(t, o, empty)
 }
 
 func TestNullLogs(t *testing.T) {
-	f, _ := New("zero")
+	ctx := setupNullTestContext(t)
+	f, _ := New(ctx, "zero")
 	o, err := f.Logs([]models.Log{{Name: "jim", Entries: []models.Entry{{Title: "title", Date: time.Now()}}}})
 	be.Err(t, err, nil)
 	be.Equal(t, o, empty)