Add Flock framework integration to Agent Integrations docs

[tilman-sattler]

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Description

This PR expands the Agent Integrations documentation to include Flock as a supported framework and clarifies the structure of the page by separating framework coverage from Diagrid-specific integration details.

The update adds a concise, conceptual Flock section focused on Dapr state store integration, including a minimal Python wiring example and links to official Flock documentation and runnable examples. The goal is to provide discoverability and high-level guidance in Dapr docs, while deferring implementation depth to canonical Flock resources.

Context:

Flock 0.5.600 introduced an optional Dapr-backed blackboard store, enabling distributed and swappable persistence backends through Dapr State Management without changing agent logic. This is a good fit for Agent Integrations because it helps users discover a practical, production-relevant Dapr integration pattern in the AI framework ecosystem.

This addresses the documentation interest raised in issue #5233 by adding Flock to Agent Integrations in a format consistent with the current page intent and contribution guidelines.

What Changed

• Added Flock to the Supported frameworks table
• Added a dedicated Flock framework integration section with:
  • short conceptual overview
  • minimal state-store wiring example
  • links to official docs, repository, and Dapr example set
• Reframed existing page content so Diagrid-maintained adapters are clearly grouped in their own section
• Added Next steps links to related Dapr docs for Workflows and State Management

Additional Links:

• Flock repository: https://github.com/whiteducksoftware/flock
• Flock documentation: https://whiteducksoftware.github.io/flock/
• Dapr state store guide: https://whiteducksoftware.github.io/flock/guides/dapr-state-store/
• Runnable examples: https://github.com/whiteducksoftware/flock/tree/main/examples/12-dapr
• Background/architecture write-up (blog post): https://whiteduck.de/flock-dapr-resilient-cloud-native-agent-swarms/
• Release notes: https://github.com/whiteducksoftware/flock/releases/tag/0.5.600

Issue reference

#5233

[tilman-sattler]

This PR relates to #5233 by @nmeisenzahl