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

---------

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

docs/advanced/configuration.mdx

@@ -8,7 +8,7 @@ Configure Strix using environment variables or a config file.
 ## LLM Configuration
 
 <ParamField path="STRIX_LLM" type="string" required>
-  Model name in LiteLLM format (e.g., `openai/gpt-5`, `anthropic/claude-sonnet-4-5`).
+  Model name in LiteLLM format (e.g., `anthropic/claude-sonnet-4-6`, `openai/gpt-5`).
 </ParamField>
 
 <ParamField path="LLM_API_KEY" type="string">
@@ -86,7 +86,7 @@ strix --target ./app --config /path/to/config.json
 ```json
 {
   "env": {
-    "STRIX_LLM": "openai/gpt-5",
+    "STRIX_LLM": "anthropic/claude-sonnet-4-6",
     "LLM_API_KEY": "sk-...",
     "STRIX_REASONING_EFFORT": "high"
   }
@@ -97,7 +97,7 @@ strix --target ./app --config /path/to/config.json
 
 ```bash
 # Required
-export STRIX_LLM="openai/gpt-5"
+export STRIX_LLM="anthropic/claude-sonnet-4-6"
 export LLM_API_KEY="sk-..."
 
 # Optional: Enable web search