test(fuzz): add file format compatibility fuzz tests (#2576)

SQLite generates complex databases (various page sizes, many tables,
indexes, overflow pages, large blobs) and Turso reads them back,
asserting every row matches.

Three test functions:
- fuzz_sqlite_generated_file_format: random seeds, all 6 page sizes
- fuzz_sqlite_generated_file_format_fixed_seeds: deterministic CI coverage
- fuzz_sqlite_generated_file_format_stress: 20 random iterations

Covers: #2576

Author: kumarUjjawal