feat: add reusable PowerContext skills and Agent Plugin packaging

[curryxjh]

Feature description

Add a reusable PowerContext Agent Plugin package for agents that support Agent Plugin skills and MCP configuration.

The package should provide:

• reusable PowerContext skills that describe how agents should use PowerContext Memory and Handoff;
• MCP configuration for the existing PowerContext Streamable HTTP MCP endpoint;
• Agent Plugin packaging so compatible agents can load the same package.

This creates a shared integration package for future agent integrations.

Problem and proposed solution

PowerContext exposes Memory and Handoff operations through its existing MCP endpoint. Agents that support Agent Plugin skills and MCP configuration should be able to reuse the same PowerContext guidance and MCP setup instead of defining similar instructions separately for each agent.

The proposed solution is to add a reusable Agent Plugin package containing PowerContext skills and MCP configuration.

The package should reuse the existing PowerContext MCP endpoint and tool surface. It should not duplicate Runtime or Memory behavior. Memory search, writes, revisions, Handoff behavior, and persistence remain owned by the PowerContext Server and existing MCP tools.

The work can be split into two PRs:

1. define reusable PowerContext skills;
2. add reusable MCP configuration and Agent Plugin packaging.

Alternatives considered

No response

Additional context

This follows the discussion in #1213.

The maintainer suggested defining reusable PowerContext skills and MCP configuration, then packaging them as an Agent Plugin. This can be split into two PRs and may support multiple agents through the same package.

Are you willing to contribute to this feature?

• Yes, I am willing to contribute code, docs, or design feedback.