refactor: extract shared CardStore into internal/store to eliminate duplication

FindCardDirectory, FindOrCreateCardDirectory, GenerateCardID and the
ScanWords helper previously existed in both internal/utils.go (as
standalone functions) and were partially duplicated in
internal/gui/card_service.go (readWordFromDir, ScanExistingWords).

Introduce internal/store.CardStore as the single source of truth for
all on-disk card-directory operations. Both internal/processor and
internal/gui now hold a *store.CardStore field and delegate to it,
removing the last copy of the directory-scanning loop from
card_service.go. internal/utils.go keeps thin forwarding wrappers for
callers that import the root internal package.

Also adds table-driven unit tests for the new package covering
FindCardDirectory (including legacy _word.txt fallback),
FindOrCreateCardDirectory, and CardStore.ScanWords.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/internal/processor/processor.go b/internal/processor/processor.go
index 14e5341..323df23 100644
--- a/internal/processor/processor.go
+++ b/internal/processor/processor.go
@@ -17,6 +17,7 @@ import (
 	"codeberg.org/snonux/totalrecall/internal/gui"
 	"codeberg.org/snonux/totalrecall/internal/image"
 	"codeberg.org/snonux/totalrecall/internal/phonetic"
+	"codeberg.org/snonux/totalrecall/internal/store"
 	"codeberg.org/snonux/totalrecall/internal/translation"
 )
 
@@ -77,6 +78,11 @@ type Processor struct {
 	// so individual methods never call Viper directly.
 	cfg *Config
 
+	// cardStore is the shared CardStore for locating and creating on-disk
+	// card directories. It is initialised from flags.OutputDir in NewProcessor
+	// and used by all card_store.go helpers.
+	cardStore *store.CardStore
+
 	// imageFactories groups the two image-provider construction functions.
 	// Production code uses image.DefaultClientFactories(); tests replace fields.
 	imageFactories image.ClientFactories
@@ -103,6 +109,9 @@ func NewProcessor(flags *cli.Flags, cfg *Config) *Processor {
 		translationCache: translation.NewTranslationCache(),
 		phoneticFetcher:  phonetic.NewFetcher(&phonetic.Config{Provider: phoneticProvider, OpenAIKey: openAIKey, GoogleAPIKey: googleAPIKey}),
 		randomIntn:       rand.Intn,
+		// cardStore is rooted at the output directory so card-discovery helpers
+		// never need to know about flags directly.
+		cardStore:        store.New(flags.OutputDir),
 		imageFactories:   image.DefaultClientFactories(),
 		newAudioProvider: audio.NewProvider,
 	}