docs: add comprehensive LF-format documentation

[deborahjacob-botanu]

Add complete documentation structure following Linux Foundation format:

Getting Started:

• installation.md - Package installation and extras
• quickstart.md - 5-minute guide to cost attribution
• configuration.md - Environment variables and YAML config

Concepts:

• architecture.md - Thin SDK / smart collector design
• run-context.md - Run model and UUIDv7 generation
• context-propagation.md - W3C Baggage propagation

Tracking:

• llm-tracking.md - LLM/GenAI tracking with OTel semconv
• data-tracking.md - Database, storage, messaging tracking
• outcomes.md - Business outcome recording

Integration:

• auto-instrumentation.md - Automatic library instrumentation
• existing-otel.md - Integration with existing OTel setups
• collector.md - OTel Collector configuration for cost calc

Patterns:

• best-practices.md - Recommended patterns
• anti-patterns.md - Common mistakes to avoid

API Reference:

• decorators.md - @botanu_use_case, @botanu_outcome
• tracking.md - Tracking context managers and helpers
• configuration.md - BotanuConfig and enable() API

Summary

Changes

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• CI / build / tooling

Testing

• Unit tests pass (pytest)
• Lint passes (ruff check)
• Type check passes (mypy)

Checklist

• My code follows the project's coding style
• I have added SPDX headers to new files
• I have added tests for my changes
• I have updated documentation if needed
• All commits are signed off (git commit -s) per the DCO