providers: add Claude Code SDK provider integration

[KJ7LNW]

Enable Claude Code SDK authentication via Claude Code CLI without requiring API keys. The Claude SDK provider complements existing API-based providers by supporting local authentication through the installed Claude Code tool.

This integration allows users with Claude Code subscriptions to leverage their existing Claude Code CLI installation for translation tasks without managing API keys or paying per token. The provider implements the same interface as other providers while using the claude-agent-sdk for communication with the locally authenticated Claude service.

• add claude-agent-sdk dependency
• add CLAUDE_SDK enum variant for provider type identification
• register CLAUDE_SDK as local provider requiring no API key
• implement ClaudeSdkProvider with multiple model support and fallbacks
• register new provider in initialization pipeline
• document Claude SDK usage in CLI help with example

[KJ7LNW]

Force pushed to clear out an unintentionally deleted comment about Ollama.

[KJ7LNW]

Okay, I'm pulling this out of draft. It is working.

I've done hundreds of translations so far without issue.

[pescheck-bram]

There are some issues with flake8 and pylint:

python_gpt_po/services/providers/claude_sdk_provider.py:5:1: F401 'logging' imported but unused
python_gpt_po/services/providers/claude_sdk_provider.py:6:1: F401 'sys' imported but unused
python_gpt_po/services/providers/provider_init.py:4:1: F401 'logging' imported but unused

[KJ7LNW]

fixed.

[pescheck-bram]

fixed.

Imports are incorrectly sorted and/or formatted.

Run isort --check-only --diff .
ERROR: /home/runner/work/python-gpt-po/python-gpt-po/python_gpt_po/services/providers/claude_sdk_provider.py Imports are incorrectly sorted and/or formatted.
--- /home/runner/work/python-gpt-po/python-gpt-po/python_gpt_po/services/providers/claude_sdk_provider.py:before	2025-12-30 09:37:03.074886
+++ /home/runner/work/python-gpt-po/python-gpt-po/python_gpt_po/services/providers/claude_sdk_provider.py:after	2025-12-30 09:37:26.814133
@@ -58,14 +58,8 @@
             raise ValueError("Claude SDK client not initialized")
 
         import anyio
-        from claude_agent_sdk import (
-            AssistantMessage,
-            CLINotFoundError,
-            ClaudeAgentOptions,
-            ProcessError,
-            TextBlock,
-            query,
-        )
+        from claude_agent_sdk import (AssistantMessage, ClaudeAgentOptions, CLINotFoundError, ProcessError, TextBlock,
+                                      query)
 
         async def get_translation():
             """Async function to get translation from Claude SDK."""
Skipped 1 files

[KJ7LNW]

fixed and rebased

[KJ7LNW]

It looks like Python 3.9 failed, but the dependency does require 3.10. Would you like this to be conditionally available if someone pip installs the claude sdk package, or do you want to drop support for 3.9?