chore: update deprecated Claude Sonnet model to claude-sonnet-4-6

[Manish-kumar-DEV]

What this PR does

Updates all references to the deprecated Anthropic Claude model "claude-sonnet-4-20250514" to "claude-sonnet-4-6" across code, examples, and documentation to prevent deprecation errors.

Kind of change

• Fix to an existing lesson
• Docs / website / tooling

Checklist

• Code runs without errors with the listed dependencies
• Tested locally / code output matches what docs/en.md claims

Phase / lesson

Affects multiple lessons across:

• Phase 00 · 04-apis-and-keys
• Phase 11 · LLM Engineering (Lessons 06, 07, 09, 10, 11, and 13)

Notes for reviewer

Since "claude-sonnet-4-20250514" is deprecated by Anthropic, this PR systematically upgrades all instances of it in code files (first_api_call.py, production_app.py) and matching documentation pages (docs/en.md across multiple lessons) to the stable "claude-sonnet-4-6" identifier. All replacements are clean and balanced (15 insertions, 15 deletions).

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 6da31bd6-064a-4b39-8135-515901097470

📥 Commits

Reviewing files that changed from the base of the PR and between 155756e and 0214377.

📒 Files selected for processing (2)

• phases/00-setup-and-tooling/04-apis-and-keys/code/first_api_call.py
• phases/11-llm-engineering/13-production-app/code/production_app.py

🚧 Files skipped from review as they are similar to previous changes (2)

• phases/00-setup-and-tooling/04-apis-and-keys/code/first_api_call.py
• phases/11-llm-engineering/13-production-app/code/production_app.py

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📝 Walkthrough

Walkthrough

This PR updates the Anthropic Claude model identifier from claude-sonnet-4-20250514 to claude-sonnet-4-6 across initial API examples, LLM engineering lesson documentation, and the production app capstone; it also adds docstrings in initial helpers and the production sample code. No control flow or functionality is altered.

Changes

Claude Model Identifier Update

Layer / File(s)	Summary
Initial API call examples phases/00-setup-and-tooling/04-apis-and-keys/code/first_api_call.py, phases/00-setup-and-tooling/04-apis-and-keys/docs/en.md	Model identifier updated in SDK-based and raw HTTP API call examples, and corresponding documentation for Python SDK, TypeScript SDK, and HTTP request snippets; brief docstrings added to the two helper functions.
LLM engineering lesson examples phases/11-llm-engineering/06-rag/docs/en.md, phases/11-llm-engineering/07-advanced-rag/docs/en.md, phases/11-llm-engineering/09-function-calling/docs/en.md, phases/11-llm-engineering/10-evaluation/docs/en.md, phases/11-llm-engineering/11-caching-cost/docs/en.md	Model identifier updated across RAG, Advanced RAG, Function Calling tool-use, Evaluation, and Prompt Caching lesson documentation examples.
Production app capstone phases/11-llm-engineering/13-production-app/code/production_app.py, phases/11-llm-engineering/13-production-app/docs/en.md	ModelName.CLAUDE_SONNET enum value updated in code and documentation snippets; numerous docstrings added/clarified across the production sample code (no logic changes).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: updating a deprecated Claude model identifier across the codebase.
Description check	✅ Passed	The description is directly related to the changeset, explaining what was updated (deprecated model references), why (to prevent deprecation errors), and which files/lessons were affected.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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