DOC-007: Add Godoc Examples for Core Packages

[ajitpratap0]

Summary

Add runnable godoc examples to all core packages to improve discoverability and usability on pkg.go.dev.

Problem

Missing runnable examples in package docs - users can't see working code on pkg.go.dev.

Action Items

1. Add godoc examples to core packages:

   • pkg/sql/tokenizer:
     • Example_Tokenize() - Basic tokenization
     • Example_TokenizeWithPool() - Pool usage
     • Example_ErrorHandling() - Error handling
   • pkg/sql/parser:
     • Example_Parse() - Basic parsing
     • Example_ParseError() - Error recovery
     • Example_ComplexQuery() - Window functions, CTEs
   • pkg/sql/ast:
     • Example_Visitor() - AST traversal
     • Example_Walk() - Tree walking
     • Example_NodeAccess() - Accessing node data
   • pkg/gosqlx:
     • Example_Parse() - Simple API
     • Example_Validate() - Validation
     • Example_Format() - Formatting

2. Add examples for each major public function

3. Ensure all examples are runnable with go test

4. Add Output: comments to show expected results

Acceptance Criteria

• 20+ godoc examples across packages
• All examples runnable (go test -run Example)
• Visible on pkg.go.dev
• Cover common use cases
• Include error handling patterns

Technical Details

Priority: Medium
Effort: Medium (20h)
Phase: Phase 3 - UX & Documentation
Dependencies: None

Example Template

func Example_basicParsing() {
    ast, err := gosqlx.Parse("SELECT * FROM users")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Parsed %d statements\n", len(ast.Statements))
    // Output: Parsed 1 statements
}