Add comprehensive Golang basics documentation with runnable examples

[Copilot]

The repository needed Golang basic explanations and examples ("Penjelasan Golang Basic").

Changes

Documentation

• README.md: Complete Golang fundamentals guide in Indonesian covering data types, control flow, functions, structs, interfaces, concurrency, and error handling with usage examples and resource links

Example Files (examples/)

11 runnable Go programs demonstrating core concepts:

• Data fundamentals: Types, variables, constants, operators
• Control structures: Conditionals, loops, switches, range iteration
• Functions: Declarations, closures, recursion, defer, variadic parameters
• Data structures: Arrays, slices, maps with operations
• OOP patterns: Structs, methods, embedding, interfaces, polymorphism
• Concurrency: Goroutines, channels, WaitGroups, mutexes, worker pools
• Error handling: Custom errors, wrapping, panic/recover

Infrastructure

• .gitignore: Excludes build artifacts and Go module cache

All examples are self-contained, compile-ready, and demonstrate idiomatic Go patterns.

Example from 05_functions.go:

// Closure - function returning function
func makeCounter() func() int {
    count := 0
    return func() int {
        count++
        return count
    }
}

Original prompt

Penjelasan Golang Basic

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