Implement local SQLite index database with repositories

- Add SQLite database connection management with proper error handling
- Implement schema for files, chunks, blobs, and snapshots tables
- Create repository pattern for each database table
- Add transaction support with proper rollback handling
- Integrate database module with fx dependency injection
- Make index path configurable via VAULTIK_INDEX_PATH env var
- Add fatal error handling for database integrity issues
- Update DESIGN.md to clarify file_chunks vs chunk_files distinction
- Remove FinalHash from BlobInfo (blobs are content-addressable)
- Add file metadata support (mtime, ctime, mode, uid, gid, symlinks)

internal/cli/entry_test.go

@@ -12,11 +12,11 @@ func TestCLIEntry(t *testing.T) {
 	if cmd == nil {
 		t.Fatal("NewRootCommand() returned nil")
 	}
-	
+
 	if cmd.Use != "vaultik" {
 		t.Errorf("Expected command use to be 'vaultik', got '%s'", cmd.Use)
 	}
-	
+
 	// Verify all subcommands are registered
 	expectedCommands := []string{"backup", "restore", "prune", "verify", "fetch"}
 	for _, expected := range expectedCommands {
@@ -31,7 +31,7 @@ func TestCLIEntry(t *testing.T) {
 			t.Errorf("Expected command '%s' not found", expected)
 		}
 	}
-	
+
 	// Verify backup command has proper flags
 	backupCmd, _, err := cmd.Find([]string{"backup"})
 	if err != nil {
@@ -47,4 +47,4 @@ func TestCLIEntry(t *testing.T) {
 			t.Error("Backup command missing --cron flag")
 		}
 	}
-}
+}