docs(python): document Ollama plugin parity features (config schema, reasoning, callable headers, timeouts)

[cabljac]

The Python Ollama plugin recently reached feature parity with JS/Go (umbrella #5521, PRs genkit-ai/genkit#5657 genkit-ai/genkit#5658 genkit-ai/genkit#5659 genkit-ai/genkit#5660). The docsite Python section is now behind.

File: src/content/docs/docs/integrations/ollama.mdx, <Lang lang="python"> block (currently ~L275-540).

Missing, all shipped in the plugin and covered in its README (py/plugins/ollama/README.md):

• OllamaConfig config schema: think, keepAlive, numCtx, minP, seed, numPredict (+ extra='allow' passthrough for newer sampler knobs)
• Reasoning models: config=OllamaConfig(think=True) and the low/medium/high levels; reasoning surfaces as a separate part
• Callable / async request_headers for expiring auth tokens (resolved per request via RequestHeaderParams). The Python "Authentication" section only shows the static dict; the JS section already documents the callable form.
• timeout kwarg on the plugin
• OllamaConnectionError (raised on an unreachable server) in troubleshooting

The plugin README is the reference for the exact API and examples.