rmcp-v3.5.0

Added

• update LATEST and add LATEST_WITH_INITIALIZE (#1105)

Fixed

• (model) decode float fields through serde_json::Number (#1300)
• (rmcp) reject duplicate sep-2243 headers (#1274)
• (transport) match explicit default ports in Origin allowlist (#1270)
• (rmcp) tolerate empty cacheScope instead of silently dropping the whole result (#1281)
• (model) preserve explicit null structuredContent in CallToolResult (#1295)

Other

• cargo fmt fixes on validate_standard_headers changes (#1275)