SQLite DB initialization & schema setup

[seojeongm]

Summary

Create telescode.db with all 6 tables (file, class, base_class, function, param, link), indexes, and PRAGMA settings (WAL, foreign_keys, synchronous).

Tasks

• sqlite3_open wrapper with error handling
• Execute all CREATE TABLE statements (Spec v1.2)
• Execute all CREATE INDEX statements
• Execute PRAGMA initialization script (WAL, foreign_keys ON, synchronous NORMAL)
• Verify schema creation with a smoke test