[router] add json tool parser (#9516)

sgl-router/src/tool_parser/mod.rs

@@ -1,8 +1,8 @@
 /// Tool parser module for handling function/tool calls in model outputs
 ///
 /// This module provides infrastructure for parsing tool calls from various model formats.
-/// Phase 1 focuses on core infrastructure: types, traits, registry, and partial JSON parsing.
 pub mod errors;
+pub mod json_parser;
 pub mod partial_json;
 pub mod registry;
 pub mod state;
@@ -14,6 +14,7 @@ mod tests;
 
 // Re-export commonly used types
 pub use errors::{ToolParserError, ToolParserResult};
+pub use json_parser::JsonParser;
 pub use registry::ParserRegistry;
 pub use state::{ParsePhase, ParseState};
 pub use traits::{PartialJsonParser, ToolParser};