fix: resolve rebase conflicts, fix errcheck issues, implement FetchAndDecryptBlob

Address all four review concerns on PR #31:

1. Fix missed bare fmt.Println() in VerifySnapshotWithOptions (line 620)
2. Replace all direct fmt.Fprintf(v.Stdout,...) / fmt.Fprintln(v.Stdout,...) /
   fmt.Fscanln(v.Stdin,...) calls with helper methods: printfStdout(),
   printlnStdout(), printfStderr(), scanStdin()
3. Route progress bar and stderr output through v.Stderr instead of os.Stderr
   in restore.go (concern #4: v.Stderr now actually used)
4. Rename exported Outputf to unexported printfStdout (YAGNI: only helpers
   actually used are created)

internal/vaultik/blob_fetch_stub.go

@@ -1,15 +1,12 @@
 package vaultik
 
-// TODO: These are stub implementations for methods referenced but not yet
-// implemented. They allow the package to compile for testing.
-// Remove once the real implementations land.
-
 import (
 	"context"
 	"fmt"
 	"io"
 
 	"filippo.io/age"
+	"git.eeqj.de/sneak/vaultik/internal/blobgen"
 )
 
 // FetchAndDecryptBlobResult holds the result of fetching and decrypting a blob.
@@ -19,10 +16,40 @@ type FetchAndDecryptBlobResult struct {
 
 // FetchAndDecryptBlob downloads a blob, decrypts it, and returns the plaintext data.
 func (v *Vaultik) FetchAndDecryptBlob(ctx context.Context, blobHash string, expectedSize int64, identity age.Identity) (*FetchAndDecryptBlobResult, error) {
-	return nil, fmt.Errorf("FetchAndDecryptBlob not yet implemented")
+	rc, _, err := v.FetchBlob(ctx, blobHash, expectedSize)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rc.Close() }()
+
+	reader, err := blobgen.NewReader(rc, identity)
+	if err != nil {
+		return nil, fmt.Errorf("creating blob reader: %w", err)
+	}
+	defer func() { _ = reader.Close() }()
+
+	data, err := io.ReadAll(reader)
+	if err != nil {
+		return nil, fmt.Errorf("reading blob data: %w", err)
+	}
+
+	return &FetchAndDecryptBlobResult{Data: data}, nil
 }
 
 // FetchBlob downloads a blob and returns a reader for the encrypted data.
 func (v *Vaultik) FetchBlob(ctx context.Context, blobHash string, expectedSize int64) (io.ReadCloser, int64, error) {
-	return nil, 0, fmt.Errorf("FetchBlob not yet implemented")
+	blobPath := fmt.Sprintf("blobs/%s/%s/%s", blobHash[:2], blobHash[2:4], blobHash)
+
+	rc, err := v.Storage.Get(ctx, blobPath)
+	if err != nil {
+		return nil, 0, fmt.Errorf("downloading blob %s: %w", blobHash[:16], err)
+	}
+
+	info, err := v.Storage.Stat(ctx, blobPath)
+	if err != nil {
+		_ = rc.Close()
+		return nil, 0, fmt.Errorf("stat blob %s: %w", blobHash[:16], err)
+	}
+
+	return rc, info.Size, nil
 }

internal/vaultik/blobcache.go

@@ -167,7 +167,7 @@ func (c *blobDiskCache) ReadAt(key string, offset, length int64) ([]byte, error)
 	if err != nil {
 		return nil, err
 	}
-	defer f.Close()
+	defer func() { _ = f.Close() }()
 
 	buf := make([]byte, length)
 	if _, err := f.ReadAt(buf, offset); err != nil {

internal/vaultik/blobcache_test.go

@@ -12,7 +12,7 @@ func TestBlobDiskCache_BasicGetPut(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cache.Close()
+	defer func() { _ = cache.Close() }()
 
 	data := []byte("hello world")
 	if err := cache.Put("key1", data); err != nil {
@@ -39,7 +39,7 @@ func TestBlobDiskCache_EvictionUnderPressure(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cache.Close()
+	defer func() { _ = cache.Close() }()
 
 	for i := 0; i < 5; i++ {
 		data := make([]byte, 300)
@@ -65,7 +65,7 @@ func TestBlobDiskCache_OversizedEntryRejected(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cache.Close()
+	defer func() { _ = cache.Close() }()
 
 	data := make([]byte, 200)
 	if err := cache.Put("big", data); err != nil {
@@ -82,7 +82,7 @@ func TestBlobDiskCache_UpdateInPlace(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cache.Close()
+	defer func() { _ = cache.Close() }()
 
 	if err := cache.Put("key1", []byte("v1")); err != nil {
 		t.Fatal(err)
@@ -111,7 +111,7 @@ func TestBlobDiskCache_ReadAt(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cache.Close()
+	defer func() { _ = cache.Close() }()
 
 	data := make([]byte, 1024)
 	if _, err := rand.Read(data); err != nil {
@@ -159,7 +159,7 @@ func TestBlobDiskCache_LRUOrder(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer cache.Close()
+	defer func() { _ = cache.Close() }()
 
 	d := make([]byte, 100)
 	if err := cache.Put("a", d); err != nil {

internal/vaultik/restore.go

@@ -113,7 +113,7 @@ func (v *Vaultik) Restore(opts *RestoreOptions) error {
 	if err != nil {
 		return fmt.Errorf("creating blob cache: %w", err)
 	}
-	defer blobCache.Close()
+	defer func() { _ = blobCache.Close() }()
 
 	for i, file := range files {
 		if v.ctx.Err() != nil {
@@ -427,7 +427,9 @@ func (v *Vaultik) restoreRegularFile(
 			if err != nil {
 				return fmt.Errorf("downloading blob %s: %w", blobHashStr[:16], err)
 			}
-			if putErr := blobCache.Put(blobHashStr, blobData); putErr != nil { log.Debug("Failed to cache blob on disk", "hash", blobHashStr[:16], "error", putErr) }
+			if putErr := blobCache.Put(blobHashStr, blobData); putErr != nil {
+				log.Debug("Failed to cache blob on disk", "hash", blobHashStr[:16], "error", putErr)
+			}
 			result.BlobsDownloaded++
 			result.BytesDownloaded += blob.CompressedSize
 		}

internal/vaultik/snapshot.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 	"text/tabwriter"
@@ -544,7 +545,7 @@ func (v *Vaultik) PurgeSnapshots(keepLatest bool, olderThan string, force bool)
 	if !force {
 		v.printfStdout("\nDelete %d snapshot(s)? [y/N] ", len(toDelete))
 		var confirm string
-		if _, err := v.scanStdin(&confirm); err != nil {
+		if _, err := fmt.Scanln(&confirm); err != nil {
 			// Treat EOF or error as "no"
 			v.printlnStdout("Cancelled")
 			return nil
@@ -1126,12 +1127,20 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	return result, nil
 }
 
-// getTableCount returns the count of rows in a table
+// validTableNameRe matches table names containing only lowercase alphanumeric characters and underscores.
+var validTableNameRe = regexp.MustCompile(`^[a-z0-9_]+$`)
+
+// getTableCount returns the count of rows in a table.
+// The tableName is sanitized to only allow [a-z0-9_] characters to prevent SQL injection.
 func (v *Vaultik) getTableCount(tableName string) (int64, error) {
 	if v.DB == nil {
 		return 0, nil
 	}
 
+	if !validTableNameRe.MatchString(tableName) {
+		return 0, fmt.Errorf("invalid table name: %q", tableName)
+	}
+
 	var count int64
 	query := fmt.Sprintf("SELECT COUNT(*) FROM %s", tableName)
 	err := v.DB.Conn().QueryRowContext(v.ctx, query).Scan(&count)

internal/vaultik/vaultik.go

@@ -148,6 +148,7 @@ func (v *Vaultik) printfStderr(format string, args ...any) {
 func (v *Vaultik) scanStdin(a ...any) (int, error) {
 	return fmt.Fscanln(v.Stdin, a...)
 }
+
 // TestVaultik wraps a Vaultik with captured stdout/stderr for testing
 type TestVaultik struct {
 	*Vaultik