Fix Import Path Normalization + Getting Started Examples

[ifedayoprince]

This PR introduces two key improvements:

1. Fix: Normalize all generated import paths to POSIX forward-slash format

The Flowcraft compiler previously relied on path.relative() to generate import paths.
On Windows, this produced backslash (\) separators, which resulted in invalid ESM import statements such as:

import { startNode } from '..\src\index'

ESM imports must use POSIX forward slashes (/).
This PR ensures all generated import paths are normalized to path.posix format, making builds consistent across platforms.

2. Fix: Correct syntax + build errors in Getting Started documentation

The examples in the Getting Started page contained minor issues that prevented them from working out-of-the-box.
This PR updates the examples to:

• Use valid Flowcraft patterns
• Align Node/Step exports properly
• Reflect the current compiler behavior
• Prevent TypeScript errors during build

This ensures the first user experience with Flowcraft is smooth and error-free.
The previous documentation examples failed to compile repeatedly.

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Just trying out Flowcraft. Nice project!