A2A server support

• Adds an A2A JSON-RPC server for exposing an Oracle Database AI Agent Team.
• Supports A2A 1.x plus A2A v0.3 streaming compatibility for Gemini Enterprise.
• Adds CLI commands:
  • select-ai a2a serve
  • select-ai a2a agent-card
• Publishes a compatible Agent Card at /.well-known/agent-card.json.
• Routes A2A requests to AsyncTeam.run() and persists Oracle conversation IDs per A2A context.
• Adds Oracle-backed stores for A2A tasks and conversation context.
• Preserves structured A2UI results as A2A data artifacts.
• Adds A2A client samples for task submission/polling and blocking workflows.

Agent-history APIs

• Adds synchronous and asynchronous APIs to query:
  • USER_AI_AGENT_TEAM_HISTORY
  • USER_AI_AGENT_TASK_HISTORY
  • USER_AI_AGENT_TOOL_HISTORY
• Introduces typed event models for team executions, task executions, and tool invocations.
• Supports filtering by team, task, agent, tool, and team execution ID, with optional limits.
• Transparently reads LOB values and parses JSON tool inputs/outputs.
• Adds sync and async history-listing samples.

Profile and provider enhancements

• Adds enable() and disable() methods to Profile and AsyncProfile.
• Makes Profile.translate() and AsyncProfile.translate() language arguments optional, allowing profile defaults and provider source-language detection.
• Adds source_language and target_language to profile attributes.
• Changes profile seed to an integer.
• Prevents native-provider endpoints from being serialized into DBMS_CLOUD_AI profile attributes, while retaining them for SDK connection configuration.
• Adds profile-creation samples for AWS, Azure, and Google Cloud providers.

Synthetic data

• Removes SDK-side defaults for SyntheticDataParams.table_statistics, .priority, and .comments.
• Defers omitted values to database-side defaults.

Compatibility, test, and documentation updates

• Raises the minimum supported Python version from 3.9 to 3.10.
• Adds A2A dependencies to the CLI extra.
• Updates agent, profile, synthetic-data, and vector-index tests.
• Expands README and user-guide documentation for A2A, history APIs, profile attributes, and synthetic-data defaults.