fix: improve DSN parsing order for SQLite fallback

Parse URL first, then fallback to SQLite special cases (:memory:, .db,
.sqlite) if no scheme found or parse error. Preserves original parse
error for better diagnostics.

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

fix: use correct SQLite DSN format to prevent file creation

- Change `sqlite::memory:` to `:memory:` in all test configs
- Add special handling in Driver() for SQLite DSNs without scheme
  (:memory:, .db, .sqlite files)

The previous `sqlite::memory:` format was being interpreted as a file
path by the SQLite driver, causing unwanted file creation.

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

fix(examples): remove invalid delay from stupid_todolist mutations

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

initial commit