🔧 L0-Python v0.20.0 - Structured Retry Fixes + Canonical Runtime Alignment

L0 Python v0.20.0 fixes structured retry behavior for stream factories, improves canonical lifecycle and observability alignment with the TypeScript runtime.

⚙️ 1. Structured Stream Factory Retry Fix

• Fixed structured retry behavior so stream factory functions are called fresh on each retry attempt.
• This resolves cases where structured retries could accidentally reuse an already-consumed stream, leading to failures like:
  • locked/consumed stream errors
  • invalid retry behavior in structured()
  • invalid retry behavior in structured_array()
  • fallback retry reuse issues
• Factory-based structured flows now retry correctly across:
  • normal retries
  • fallback retries
  • sync and async stream factories

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📈 2. Canonical Lifecycle + Observability Alignment

• Improved runtime parity with the canonical lifecycle and TypeScript event model.
• Updates include:
  • FALLBACK_START now uses fromIndex / toIndex
  • retry attempts include isRetry
  • fallback attempt numbering resets correctly per fallback stream
  • error events now include richer recovery metadata
  • failure classification and recovery strategy mapping are now emitted more explicitly
• Added new canonical lifecycle and network classification tests to lock this behavior in.

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🛟 3. Network Error Classification Coverage

• Added broader canonical tests for network error detection and classification.
• Improves confidence around handling of:
  • connection drops
  • DNS failures
  • fetch/network request failures
  • timeout conditions
  • SSL-related failures
• This strengthens parity between documented behavior and tested runtime behavior.

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🗃️ 4. Documentation Updates

• Updated docs across the project for correctness and consistency, including:
  • API documentation
  • lifecycle docs
  • custom adapter docs
  • multimodal docs
  • consensus docs
  • document window docs
  • guardrails docs
  • README usage fixes
• Added a new WHITEPAPER.md describing L0 as a deterministic streaming execution substrate for AI.