Add deeper Objective-C and Swift metadata extraction, plus database
path/save/licensing behavior where licensing permits (#353).
- objcSwiftMetadata.ts: domain schemas for ObjC classes, protocols,
methods (instance/class/ivar getter/setter), properties with
attributes, and Swift declarations (class, struct, enum, protocol,
extension, actor) with access levels and modifiers.
- Database save/readback operation tracking with preserved names,
comments, and bookmarks verification.
- Utility functions for selector classification, method counting,
Swift declaration filtering, and database save completeness.
- Read-only and mutating operations are distinguished.
Closes#353
