refactor: split store.go into focused files by responsibility (task o6)

Split 562-line store.go into four files:
- store.go (264 lines): Store type, WalkIndexes, Search, action dispatch
- store_crud.go (160 lines): Add, Import, Remove, buildPair
- store_picker.go (160 lines): Fzf, PickerResult, key parsing
- store_shred.go (54 lines): ShredFile, ShredAllExported

No API or behaviour changes. All functions under 30 lines, all files under 300 lines.

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

1 files changed, 160 insertions, 0 deletions

diff --git a/internal/store/store_picker.go b/internal/store/store_picker.go
new file mode 100644
index 0000000..1e8b6b7
--- /dev/null
+++ b/internal/store/store_picker.go
@@ -0,0 +1,160 @@
+// store_picker.go handles fzf/picker integration for the interactive secret browser.
+// It wraps the internal/picker package to provide fuzzy-selection with action key
+// bindings (cat, paste, open, edit) and maps the raw fzf output back to typed
+// PickerResult values consumed by the CLI layer.
+package store
+
+import (
+	"context"
+	"os"
+	"sort"
+	"strings"
+
+	"codeberg.org/snonux/foostore/internal/picker"
+)
+
+// PickerAction describes the action requested from the interactive fzf picker.
+type PickerAction string
+
+const (
+	PickerSelect PickerAction = "select"
+	PickerCat    PickerAction = "cat"
+	PickerPaste  PickerAction = "paste"
+	PickerOpen   PickerAction = "open"
+	PickerEdit   PickerAction = "edit"
+)
+
+// PickerResult is the selected description plus the desired action from fzf.
+// Description is empty when the picker was cancelled.
+type PickerResult struct {
+	Description string
+	Action      PickerAction
+}
+
+// Fzf launches fzf and returns only the selected description for compatibility
+// with callers that do not care about picker action keys.
+func (s *Store) Fzf(ctx context.Context) (string, error) {
+	result, err := s.FzfInteractive(ctx)
+	if err != nil {
+		return "", err
+	}
+	return result.Description, nil
+}
+
+// FzfInteractive launches fzf with helper bars, preview metadata, and action
+// key bindings, then returns both the selected description and action.
+func (s *Store) FzfInteractive(ctx context.Context) (PickerResult, error) {
+	var indexes IndexSlice
+	if err := s.WalkIndexes(ctx, "", func(idx *Index) error {
+		indexes = append(indexes, idx)
+		return nil
+	}); err != nil {
+		return PickerResult{}, err
+	}
+	if len(indexes) == 0 {
+		return PickerResult{}, nil
+	}
+
+	sort.Sort(indexes)
+	entries := buildPickerEntries(indexes)
+
+	return runFzfInteractive(ctx, entries)
+}
+
+// buildPickerEntries converts a sorted IndexSlice into picker.Entry values,
+// annotating each entry with its kind (TEXT/BINARY) and a short hash suffix
+// for visual disambiguation in the fzf list.
+func buildPickerEntries(indexes IndexSlice) []picker.Entry {
+	entries := make([]picker.Entry, 0, len(indexes))
+	for i, idx := range indexes {
+		kind := "TEXT"
+		if idx.IsBinary() {
+			kind = "BINARY"
+		}
+		hashSuffix := ""
+		if len(idx.Hash) >= 63 {
+			hashSuffix = idx.Hash[53:63]
+		}
+		entries = append(entries, picker.Entry{
+			RowID:       i + 1,
+			Description: idx.Description,
+			Kind:        kind,
+			HashSuffix:  hashSuffix,
+		})
+	}
+	return entries
+}
+
+// runFzfInteractive delegates to picker.Run, then maps the raw fzf selection
+// (key line + description) to a typed PickerResult. An empty or cancelled
+// selection returns a zero PickerResult without error.
+func runFzfInteractive(ctx context.Context, entries []picker.Entry) (PickerResult, error) {
+	selection, err := picker.Run(ctx, entries)
+	if err != nil {
+		return PickerResult{}, err
+	}
+
+	action, ok := parsePickerAction(selection.Key)
+	if !ok {
+		return PickerResult{}, nil
+	}
+	if selection.Description == "" {
+		return PickerResult{}, nil
+	}
+
+	return PickerResult{
+		Description: selection.Description,
+		Action:      action,
+	}, nil
+}
+
+// buildFzfArgs returns the fzf argument slice for the given entry count,
+// reading FOOSTORE_TUI_THEME and FOOSTORE_FZF_OPTS from the environment.
+// Delegates to picker.BuildArgs so that the fzf argument format stays in one place.
+func buildFzfArgs(entryCount int) []string {
+	return picker.BuildArgs(
+		entryCount,
+		os.Getenv("FOOSTORE_TUI_THEME"),
+		os.Getenv("FOOSTORE_FZF_OPTS"),
+	)
+}
+
+// pickerColorTheme returns the fzf --color string for the named TUI theme.
+// Delegates to picker.ColorTheme; unknown names fall back to the bold preset.
+func pickerColorTheme(theme string) string {
+	return picker.ColorTheme(theme)
+}
+
+// parsePickerResult decodes a raw fzf --expect output string into a PickerResult.
+// idToDescription maps row-ID strings back to their human-readable descriptions.
+// Returns a zero PickerResult when the key is unknown or the selection is empty.
+func parsePickerResult(output string, idToDescription map[string]string) PickerResult {
+	selection := picker.ParseSelection(output, idToDescription)
+	action, ok := parsePickerAction(selection.Key)
+	if !ok || selection.Description == "" {
+		return PickerResult{}
+	}
+	return PickerResult{
+		Description: selection.Description,
+		Action:      action,
+	}
+}
+
+// parsePickerAction maps an fzf key line (e.g. "ctrl-t", "enter") to a typed
+// PickerAction. Returns (action, true) on a recognised key, ("", false) otherwise.
+func parsePickerAction(keyLine string) (PickerAction, bool) {
+	switch strings.TrimSpace(keyLine) {
+	case "", "enter":
+		return PickerSelect, true
+	case "ctrl-t", "alt-t":
+		return PickerCat, true
+	case "ctrl-y", "alt-y":
+		return PickerPaste, true
+	case "ctrl-o", "alt-o":
+		return PickerOpen, true
+	case "ctrl-e", "alt-e":
+		return PickerEdit, true
+	default:
+		return "", false
+	}
+}