Document the connect() timeout split and safety caps

stdlib's timeout is the busy-wait budget; here timeout is a per-RPC-phase
deadline and busy_timeout is the SQLITE_BUSY budget, which silently trips up
ports from sqlite3. Note the distinction plus the message/continuation/row
safety caps and trust_server_heartbeat.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: antoineleclair

docs/differences-from-sqlite3.md

@@ -22,6 +22,11 @@ covers the differences you are most likely to notice when porting code.
   SQLite's legacy unenforced behavior.
 - **SERIALIZABLE isolation only.** Every statement is ordered by Raft;
   weaker isolation levels are not exposed.
+- **`connect()` timeouts differ from stdlib.** stdlib's `timeout` is the
+  busy (lock-wait) budget; here `timeout` is a per-RPC-phase deadline and
+  the busy budget is the separate `busy_timeout` argument. `connect()` also
+  exposes safety caps — `max_message_size`, `max_continuation_frames`,
+  `max_total_rows` — and `trust_server_heartbeat`.
 - **Result sets are fully materialized at `execute()` time.** Stdlib streams
   rows lazily from the C engine; dqlite drains every continuation frame into
   the cursor's in-memory buffer before `execute()` returns, and `fetchone()`