chore: update model references to Claude 4.6 and GPT-5.2

- Claude Opus 4.5 → Opus 4.6, Claude Sonnet 4.5 → Sonnet 4.6 (Haiku stays 4.5)
- Update claude-sonnet-4-5 model IDs to claude-sonnet-4-6 in code examples
- Update SWE-bench stat from 80.9% to 80.8% for Opus 4.6
- Update GPT refs: GPT-5 → GPT-5.2, GPT-4o → gpt-5.2, GPT-4o-mini → GPT-5-mini
- Fix GPT-5.2-mini → GPT-5-mini (correct model name per OpenAI)
- Bump marketplace to v1.5.2 and affected plugin versions

plugins/llm-application-dev/skills/langchain-architecture/SKILL.md

@@ -115,8 +115,8 @@ from langchain_core.tools import tool
 import ast
 import operator
 
-# Initialize LLM (Claude Sonnet 4.5 recommended)
-llm = ChatAnthropic(model="claude-sonnet-4-5", temperature=0)
+# Initialize LLM (Claude Sonnet 4.6 recommended)
+llm = ChatAnthropic(model="claude-sonnet-4-6", temperature=0)
 
 # Define tools with Pydantic schemas
 @tool
@@ -201,7 +201,7 @@ class RAGState(TypedDict):
     answer: str
 
 # Initialize components
-llm = ChatAnthropic(model="claude-sonnet-4-5")
+llm = ChatAnthropic(model="claude-sonnet-4-6")
 embeddings = VoyageAIEmbeddings(model="voyage-3-large")
 vectorstore = PineconeVectorStore(index_name="docs", embedding=embeddings)
 retriever = vectorstore.as_retriever(search_kwargs={"k": 4})
@@ -489,7 +489,7 @@ os.environ["LANGCHAIN_API_KEY"] = "your-api-key"
 os.environ["LANGCHAIN_PROJECT"] = "my-project"
 
 # All LangChain/LangGraph operations are automatically traced
-llm = ChatAnthropic(model="claude-sonnet-4-5")
+llm = ChatAnthropic(model="claude-sonnet-4-6")
 ```
 
 ### Custom Callback Handler
@@ -530,7 +530,7 @@ result = await agent.ainvoke(
 ```python
 from langchain_anthropic import ChatAnthropic
 
-llm = ChatAnthropic(model="claude-sonnet-4-5", streaming=True)
+llm = ChatAnthropic(model="claude-sonnet-4-6", streaming=True)
 
 # Stream tokens
 async for chunk in llm.astream("Tell me a story"):