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>

release_notes_v3.5.0.md

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+# sol-trade-sdk v3.5.0
+
+Rust SDK for Solana DEX trading (Pump.fun, PumpSwap, Raydium, Bonk, Meteora, etc.).
+
+## What's Changed
+
+### Performance
+
+- **Hot-path timing**: `Instant::now()` for build/submit/total/confirm only when `log_enabled` or (for total) simulate, reducing cold-path syscalls.
+- **Fewer clones**: `execute_parallel` now takes `&[Arc<SwqosClient>]` instead of `Vec<Arc<SwqosClient>>`; caller no longer clones the client list.
+- **SWQoS HTTP**: Named constants for pool idle timeout, connect/request timeouts, and HTTP/2 keepalive in `swqos/common.rs`.
+
+### Code quality
+
+- **Protocol params**: Single `validate_protocol_params(dex_type, params)` used by both buy and sell; removed duplicated match blocks.
+- **Constants**: `BYTES_PER_ACCOUNT`, `MAX_INSTRUCTIONS_WARN` in execution; HTTP timeout constants in swqos common.
+- **Comments**: Prefetch and branch-hint safety/usage documented; `SYSCALL_BYPASS` marked as reserved for future use.
+
+### Documentation
+
+- **Bilingual docs**: English + 中文 doc comments in `trading/core/execution.rs`, `trading/core/executor.rs`, `perf/hardware_optimizations.rs`, `perf/mod.rs`, `perf/syscall_bypass.rs`, `swqos/common.rs`.
+- **README**: Version references and "What's new in 3.5.0" (EN) / "3.5.0 更新说明" (CN) updated.
+
+---
+
+## Cargo
+
+**From Git (this release):**
+```toml
+sol-trade-sdk = { git = "https://github.com/0xfnzero/sol-trade-sdk", tag = "v3.5.0" }
+```
+
+**From crates.io** (when published):
+```toml
+sol-trade-sdk = "3.5.0"
+```
+
+**Full Changelog**: https://github.com/0xfnzero/sol-trade-sdk/compare/v3.4.1...v3.5.0