[Feature] Brief description

## Problem Description
When will agentscope-runtime support [A2A 1.0](https://a2a-protocol.org/latest/announcing-1.0/)?

Currently, agentscope-runtime uses `a2a-sdk>=0.3.0,<1.0.0` which implements the A2A 0.3 specification.

## Proposed Solution
Update agentscope-runtime to support the A2A 1.0 protocol specification by:
1. **Update dependency**: Upgrade `a2a-sdk` to a version that supports A2A 1.0 (e.g., `a2a-sdk>=1.0.0`)
2. **Update data models**: Modify `Role` enum from `agent`/`user` to `ROLE_AGENT`/`ROLE_USER`/`ROLE_UNSPECIFIED`
3. **Update AgentCard**
4. **Maintain backward compatibility**: Consider providing a compatibility layer for existing 0.3 clients (or not)

## Affected Component(s)
all

## Alternatives Considered
[Describe any alternative solutions you've considered]

## Additional Context
[Any other context, screenshots, or examples about the feature request]