Strix LLM Documentation and Config Changes (#315)

* feat: add to readme new keys

* feat: shoutout strix models, docs

* fix: mypy error

* fix: base api

* docs: update quickstart and models

* fixes: changes to docs

uniform api_key variable naming

* test: git commit hook

* nevermind it was nothing

* docs: Update default model to claude-sonnet-4.6 and improve Strix Router docs

- Replace gpt-5 and opus-4.6 defaults with claude-sonnet-4.6 across all docs and code
- Rewrite Strix Router (models.mdx) page with clearer structure and messaging
- Add Strix Router as recommended option in overview.mdx and quickstart prerequisites
- Update stale Claude 4.5 references to 4.6 in anthropic.mdx, openrouter.mdx, bug_report.md
- Fix install.sh links to point to models.strix.ai and correct docs URLs
- Update error message examples in main.py to use claude-sonnet-4-6

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Co-authored-by: 0xallam <ahmed39652003@gmail.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -27,7 +27,7 @@ If applicable, add screenshots to help explain your problem.
 - OS: [e.g. Ubuntu 22.04]
 - Strix Version or Commit: [e.g. 0.1.18]
 - Python Version: [e.g. 3.12]
-- LLM Used: [e.g. GPT-5, Claude Sonnet 4]
+- LLM Used: [e.g. GPT-5, Claude Sonnet 4.6]
 
 **Additional context**
 Add any other context about the problem here.