e2.0.0 Init and config pattern changed, builder added, docs updated, examples removed (deprecated).

doc/config-builder.md

@@ -0,0 +1,71 @@
+# Builder Pattern Guide
+
+The ConfigBuilder provides a fluent API for constructing logger configurations with compile-time safety and deferred validation.
+
+## Creating a Builder
+
+NewConfigBuilder creates a new configuration builder initialized with default values.
+
+```go
+func NewConfigBuilder() *ConfigBuilder
+```
+
+```go
+builder := log.NewConfigBuilder()
+```
+
+## Builder Methods
+
+All builder methods return `*ConfigBuilder` for chaining. Errors are accumulated and returned by `Build()`.
+
+### Common Methods
+
+| Method | Parameters | Description |
+|--------|------------|-------------|
+| `Level(level int64)` | `level`: Numeric log level | Sets log level (-4 to 8) |
+| `LevelString(level string)` | `level`: Named level | Sets level by name ("debug", "info", etc.) |
+| `Directory(dir string)` | `dir`: Path | Sets log directory |
+| `Format(format string)` | `format`: Output format | Sets format ("txt", "json", "raw") |
+| `BufferSize(size int64)` | `size`: Buffer size | Sets channel buffer size |
+| `MaxSizeMB(size int64)` | `size`: Size in MB | Sets max file size |
+| `EnableStdout(enable bool)` | `enable`: Boolean | Enables console output |
+| `DisableFile(disable bool)` | `disable`: Boolean | Disables file output |
+| `HeartbeatLevel(level int64)` | `level`: 0-3 | Sets monitoring level |
+
+## Build
+
+```go
+func (b *ConfigBuilder) Build() (*Config, error)
+```
+
+Validates builder configuration and returns logger config.
+Returns accumulated errors if any builder operations failed.
+
+```go
+cfg, err := builder.Build()
+if err != nil {
+    // Handle validation or conversion errors
+}
+```
+
+## Usage pattern
+
+```go
+logger := log.NewLogger()
+
+cfg, err := log.NewConfigBuilder().
+    Directory("/var/log/app").
+    Format("json").
+    LevelString("debug").
+    Build()
+
+if err != nil {
+    return err
+}
+
+err = logger.ApplyConfig(cfg)
+```
+
+---
+
+[← Configuration](configuration.md) | [← Back to README](../README.md) | [API Reference →](api-reference.md)