feat(database): add file size metadata and range parameters

- Add byte_size and line_count columns to files table
- Increment SchemaVersion to 2 (requires re-indexing)
- Add DeclarationWithMetadata, FileRange, FileResult types
- Add GetDeclarationsWithMetadata method for file metadata lookup
- Add GetFileWithRange method for paginated file retrieval
- Implement countLines and applyLineRange helpers

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/database/interface.go

@@ -44,6 +44,30 @@ type File struct {
 	FilePath   string
 	Extension  string
 	Content    string
+	ByteSize   int
+	LineCount  int
+}
+
+// DeclarationWithMetadata includes declaration info plus file metadata.
+type DeclarationWithMetadata struct {
+	Declaration
+	ByteSize  int  // File size in bytes, 0 if file not indexed
+	LineCount int  // Number of lines, 0 if file not indexed
+	HasFile   bool // True if file is indexed
+}
+
+// FileRange specifies a range of lines to return from a file.
+type FileRange struct {
+	Offset int // Line offset (0-based)
+	Limit  int // Maximum lines to return (0 = default 250)
+}
+
+// FileResult contains a file with range metadata.
+type FileResult struct {
+	*File
+	TotalLines int // Total lines in the file
+	StartLine  int // First line returned (1-based)
+	EndLine    int // Last line returned (1-based)
 }
 
 // SearchFilters contains optional filters for option search.
@@ -80,9 +104,11 @@ type Store interface {
 	CreateDeclaration(ctx context.Context, decl *Declaration) error
 	CreateDeclarationsBatch(ctx context.Context, decls []*Declaration) error
 	GetDeclarations(ctx context.Context, optionID int64) ([]*Declaration, error)
+	GetDeclarationsWithMetadata(ctx context.Context, revisionID, optionID int64) ([]*DeclarationWithMetadata, error)
 
 	// File operations
 	CreateFile(ctx context.Context, file *File) error
 	CreateFilesBatch(ctx context.Context, files []*File) error
 	GetFile(ctx context.Context, revisionID int64, path string) (*File, error)
+	GetFileWithRange(ctx context.Context, revisionID int64, path string, r FileRange) (*FileResult, error)
 }