refactor(streaming): unify preprocessing and add queued stream sources

[pythonscriptsPro]

📝 Description

This PR refactors and hardens the streaming data pipeline to support reliable real-time inference.
It introduces queued, background-driven stream sources (Webcam, Video, MQTT, TCP) to decouple capture/receive rates from inference speed, and unifies preprocessing by moving all transform logic into the dataset layer.

The changes fix multiple streaming stability issues (thread lifecycle, blocking I/O, dataset length assumptions) and align streaming behavior with the existing offline dataset contract.

✨ Changes

Select the type of change in this PR:

• 🚀 New feature (adds functionality without breaking existing behavior)
• 🐞 Bug fix (resolves an issue without breaking existing behavior)
• 🔄 Refactor (improves code structure without changing behavior)
• ⚡ Performance improvement
• 🎨 Style update (formatting/code style only)
• 🧪 Tests (add/modify tests)
• 📚 Documentation update
• 📦 Build system change
• 🚧 CI/CD configuration
• 🔧 Chore (maintenance tasks)
• 🔒 Security update
• 💥 Breaking change (feature or fix that changes existing behavior)

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✅ Checklist

Before submitting, confirm the following:

• 📚 Documentation updated (if applicable)
• 🧪 Tests added/updated (if applicable)
• 🏷️ PR title follows conventional commits

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