feat: add Go, PHP, and Laravel SDKs

- Go SDK: zero deps, functional options pattern, full endpoint coverage
- PHP SDK: PHP 8.1+, curl-based, PdfOptions class, PSR-4 autoloading
- Laravel package: ServiceProvider, Facade, config publishing
- All SDKs document complete PDF options including new v0.4.5 params

sdk/go/README.md

@@ -0,0 +1,151 @@
+# DocFast Go SDK
+
+Official Go client for the [DocFast](https://docfast.dev) HTML/Markdown to PDF API.
+
+## Installation
+
+```bash
+go get github.com/docfast/docfast-go
+```
+
+## Quick Start
+
+```go
+package main
+
+import (
+	"os"
+	docfast "github.com/docfast/docfast-go"
+)
+
+func main() {
+	client := docfast.New("df_pro_your_api_key")
+
+	// HTML to PDF
+	pdf, err := client.HTML("<h1>Hello World</h1><p>Generated with DocFast</p>", nil)
+	if err != nil {
+		panic(err)
+	}
+	os.WriteFile("output.pdf", pdf, 0644)
+}
+```
+
+## Usage
+
+### HTML to PDF
+
+```go
+pdf, err := client.HTML("<h1>Hello</h1>", &docfast.PDFOptions{
+	Format:    "A4",
+	Landscape: true,
+	Margin:    &docfast.Margin{Top: "20mm", Bottom: "20mm"},
+})
+```
+
+### HTML with custom CSS
+
+```go
+pdf, err := client.HTMLWithCSS(
+	"<h1>Styled</h1>",
+	"h1 { color: navy; font-family: Georgia; }",
+	nil,
+)
+```
+
+### Markdown to PDF
+
+```go
+pdf, err := client.Markdown("# Report\n\nGenerated **automatically**.", nil)
+```
+
+### URL to PDF
+
+```go
+pdf, err := client.URL("https://example.com", &docfast.PDFOptions{
+	Format:          "Letter",
+	PrintBackground: docfast.Bool(true),
+})
+```
+
+### Headers and Footers
+
+```go
+pdf, err := client.HTML(html, &docfast.PDFOptions{
+	DisplayHeaderFooter: true,
+	HeaderTemplate:      `<div style="font-size:10px;text-align:center;width:100%">My Document</div>`,
+	FooterTemplate:      `<div style="font-size:10px;text-align:center;width:100%">Page <span class="pageNumber"></span> of <span class="totalPages"></span></div>`,
+	Margin:              &docfast.Margin{Top: "40mm", Bottom: "20mm"},
+})
+```
+
+### Custom Page Size
+
+```go
+pdf, err := client.HTML(html, &docfast.PDFOptions{
+	Width:  "8.5in",
+	Height: "11in",
+	Scale:  0.8,
+})
+```
+
+### Templates
+
+```go
+// List available templates
+templates, err := client.Templates()
+
+// Render a template
+pdf, err := client.RenderTemplate("invoice", map[string]interface{}{
+	"company":  "Acme Corp",
+	"items":    []map[string]interface{}{{"name": "Widget", "price": 9.99}},
+	"_format":  "A4",
+})
+```
+
+## PDF Options
+
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `Format` | string | `"A4"` | Page size: A4, Letter, Legal, A3, A5, Tabloid |
+| `Landscape` | bool | `false` | Landscape orientation |
+| `Margin` | *Margin | `nil` | Page margins (CSS units) |
+| `PrintBackground` | *bool | `true` | Print background graphics |
+| `Filename` | string | `""` | Suggested filename |
+| `HeaderTemplate` | string | `""` | HTML header template |
+| `FooterTemplate` | string | `""` | HTML footer template |
+| `DisplayHeaderFooter` | bool | `false` | Show header/footer |
+| `Scale` | float64 | `1` | Rendering scale (0.1–2.0) |
+| `PageRanges` | string | `""` | Pages to print (e.g. "1-3,5") |
+| `PreferCSSPageSize` | bool | `false` | Prefer CSS @page size |
+| `Width` | string | `""` | Custom paper width |
+| `Height` | string | `""` | Custom paper height |
+
+## Error Handling
+
+```go
+pdf, err := client.HTML("<h1>Test</h1>", nil)
+if err != nil {
+	var apiErr *docfast.Error
+	if errors.As(err, &apiErr) {
+		fmt.Printf("API error: %s (status %d)\n", apiErr.Message, apiErr.StatusCode)
+	}
+}
+```
+
+## Configuration
+
+```go
+// Custom base URL (e.g. for self-hosted or staging)
+client := docfast.New("key", docfast.WithBaseURL("https://staging.docfast.dev"))
+
+// Custom HTTP client
+client := docfast.New("key", docfast.WithHTTPClient(&http.Client{
+	Timeout: 120 * time.Second,
+}))
+```
+
+## Links
+
+- [Documentation](https://docfast.dev/docs)
+- [API Reference](https://docfast.dev/openapi.json)
+- [Get an API Key](https://docfast.dev)