Add a standalone Hermes web provider example

[liuhao1024]

Problem

Hermes supports user-installed web provider plugins, but third-party product integrations are not expected to land in NousResearch/hermes-agent core. Users who want Hermes' built-in web_search and web_extract tools to route through AgentKey need a standalone plugin path rather than a core Hermes PR.

This is separate from the full AgentKey MCP integration. The MCP server remains the preferred path for dynamic tool discovery and domain-specific AgentKey tools.

Proposed Scope

Add an examples/hermes-web-provider/ directory that:

• registers an AgentKey-backed Hermes WebSearchProvider
• maps web_search to AgentKey's agentkey_search through the hosted MCP endpoint
• maps web_extract to AgentKey's agentkey_scrape
• keeps auth explicit through AGENTKEY_API_KEY
• documents installation under ~/.hermes/plugins/web/agentkey

Boundaries

• No change to AgentKey's default install path.
• No change to skills/agentkey/SKILL.md routing rules.
• No claim that this replaces the full AgentKey MCP server.
• No Hermes core plugin PR is required.

Validation Target

A PR should include offline provider tests for response normalization and a smoke test that the plugin can be loaded by Hermes as web/agentkey.