Release v3.5.0: performance, constants, bilingual docs

- Bump version to 3.5.0
- Performance: hot-path timing only when log_enabled/simulate; execute_parallel takes &[Arc<SwqosClient>]; shared HTTP client constants for SWQoS
- Code quality: validate_protocol_params extracted for buy/sell; BYTES_PER_ACCOUNT, MAX_INSTRUCTIONS_WARN, HTTP timeout constants; prefetch/syscall bypass comments
- Documentation: bilingual (EN + 中文) doc comments in execution, executor, perf, swqos; README/README_CN version and What's new in 3.5.0
- Add release_notes_v3.5.0.md

Co-authored-by: Cursor <cursoragent@cursor.com>

src/common/sdk_log.rs

@@ -0,0 +1,19 @@
+//! sol-trade-sdk global log switch
+//!
+//! Controlled by `TradeConfig::log_enabled`, set in `TradingClient::new`.
+//! All SDK logs (timing, SWQOS submit/confirm, WSOL, blacklist, etc.) should check this before output.
+
+use std::sync::atomic::{AtomicBool, Ordering};
+
+static SDK_LOG_ENABLED: AtomicBool = AtomicBool::new(true);
+
+/// Whether SDK logging is enabled (set from TradeConfig.log_enabled in TradingClient::new).
+#[inline(always)]
+pub fn sdk_log_enabled() -> bool {
+    SDK_LOG_ENABLED.load(Ordering::Relaxed)
+}
+
+/// Set the SDK global log switch (only called from TradingClient::new).
+pub fn set_sdk_log_enabled(enabled: bool) {
+    SDK_LOG_ENABLED.store(enabled, Ordering::Relaxed);
+}