docs: add Quick Start Examples section to README

Added a comprehensive "Quick Start Examples" section to help new users
get started quickly with gotests. The section includes:

Examples:
- Generate tests for a single function (with full output)
- Generate tests for all exported functions
- Generate tests recursively with ./... pattern
- Generate tests with testify template
- Common workflows with practical use cases

Each example shows both the command and explains what it does, making
it easier for users to understand how to use gotests effectively.

The examples are placed right after the options list and before the
Go Generics section for better flow and discoverability.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: cweill

README.md

@@ -65,6 +65,91 @@ Available options:
   -version              print version information and exit
 ```
 
+## Quick Start Examples
+
+### Generate tests for a single function
+
+Given a file `math.go`:
+
+```go
+package math
+
+func Add(a, b int) int {
+    return a + b
+}
+```
+
+Generate a test:
+
+```sh
+$ gotests -only Add -w math.go
+```
+
+This creates `math_test.go` with:
+
+```go
+func TestAdd(t *testing.T) {
+    type args struct {
+        a int
+        b int
+    }
+    tests := []struct {
+        name string
+        args args
+        want int
+    }{
+        // TODO: Add test cases.
+    }
+    for _, tt := range tests {
+        t.Run(tt.name, func(t *testing.T) {
+            if got := Add(tt.args.a, tt.args.b); got != tt.want {
+                t.Errorf("Add() = %v, want %v", got, tt.want)
+            }
+        })
+    }
+}
+```
+
+### Generate tests for all exported functions
+
+```sh
+$ gotests -all -exported -w .
+```
+
+This generates tests for all exported functions in the current directory.
+
+### Generate tests recursively
+
+```sh
+$ gotests -all -w ./...
+```
+
+This generates tests for all functions in the current directory and all subdirectories.
+
+### Generate tests with testify
+
+```sh
+$ gotests -all -template testify -w calculator.go
+```
+
+This generates tests using the [testify](https://github.com/stretchr/testify) assertion library.
+
+### Common workflows
+
+```sh
+# Generate tests for all exported functions in a package
+$ gotests -exported -w pkg/*.go
+
+# Generate only tests for specific functions matching a pattern
+$ gotests -only "^Process" -w handler.go
+
+# Generate tests excluding certain functions
+$ gotests -all -excl "^helper" -w utils.go
+
+# Generate parallel subtests
+$ gotests -all -parallel -w service.go
+```
+
 ## Go Generics Support
 
 `gotests` fully supports Go generics (type parameters) introduced in Go 1.18+. It automatically generates tests for generic functions and methods on generic types.