Router and JSON auto-serialization fixes

[cs01]

Router & JSON improvements: Accept any type, auto-stringify

Summary

Enhances the router's JSON response handling to accept any type and automatically stringify before serialization. Fixes route matching edge cases with explicit null/undefined checks and refactors the semantic union-type checker for better code clarity.

Changes

Router JSON Method

• lib/router.ts: Changed Context.json() to accept data: any instead of requiring pre-stringified strings
• Removed explicit JSON.stringify() call — now relies on codegen to handle stringification
• Enables seamless serialization of objects: c.json({ message: "hello" })

Route Matching Safety

• lib/router.ts: Enhanced outer group matching with explicit null/undefined checks
• Old: if (outerGroup !== "")
• New: if (outerGroup !== undefined && outerGroup !== null && outerGroup !== "")
• Prevents potential matching failures on certain regex patterns

Semantic Pass Refactoring

• src/semantic/union-type-checker.ts: Converted from class-based to function-based approach
• Removes unnecessary instance state, making logic more straightforward
• Maintains identical behavior for union type safety validation

JSON Codegen

• src/codegen/stdlib/json.ts: Added support for auto-stringifying in c.json() calls
• Handles object-to-string conversion at code generation time
• Propagates type information through generator context

Type System & Codegen Infrastructure

• src/codegen/infrastructure/generator-context.ts: Added new context methods for JSON handling
• src/codegen/llvm-generator.ts: Integrated JSON stringification logic
• src/codegen/types/objects/class.ts: Updated for proper field handling

Parser Updates

• src/parser-ts/handlers/declarations.ts: Minor adjustments for accurate parsing
• src/parser-native/transformer.ts: Matching updates in native parser
• src/parser-ts/transformer.ts: Parser consistency fixes

Type Definitions

• chadscript.d.ts: Updated Router and Context type signatures
• src/ast/types.ts: Added optional json support flags

Documentation & Tests

• docs/language/classes.md: Added class method documentation
• docs/language/features.md: Updated feature list with JSON enhancements
• tests/fixtures/router/context-json-any.ts: New test for c.json() with object literals
• tests/fixtures/router/router-named-handlers.ts: Test coverage for named handler patterns

Test Coverage

• context-json-any.ts: Validates c.json({ message: "hello" }) produces correct JSON output
• router-named-handlers.ts: Tests named handler patterns with Context

Verification

All changes verified through:

• Unit tests for JSON serialization
• Router integration tests
• Semantic analysis validation
• Type system correctness