feat: add Agent Plugins 1.0 package

[777genius]

Summary

• Add an Agent Plugins 1.0 package at the repository root.
• Expose the existing stdio server through a version-pinned mcp.json.
• Keep the package version and MCP npm pin synchronized through release-please.
• Use npx --prefix ${PLUGIN_DATA} to avoid resolving the repository's unbuilt local npm package instead of the published server. This keeps compatibility with clients that cannot represent an explicit working directory.
• Document installation through Agent Plugins CLI.

Verification

• plugin.json and mcp.json pass the Agent Plugins 1.0 schemas.
• Exact head 02372c4d47ad257773b2b80c7d7fd056d7067be0 was tested using local package bytes with the released Agent Plugins CLI 0.1.24.
• Isolated add, doctor, repair, and remove with data cleanup passed for Claude Code, Gemini CLI, OpenCode, Cline, and Windsurf. Configuration-only clients are not claimed as live model tests.
• OpenCode 1.18.25 with its built-in opencode/big-pickle model successfully called new_page and take_snapshot, recovering a random marker from a loopback test page. The marker was absent from the prompt, and other tools were denied.
• Gemini CLI 0.57.0 reported the MCP server as connected. Its model call was blocked by Google account eligibility, so Gemini model runtime is not claimed.
• Package tree: sha256:50145f0cfd0e4095cfb00fc74755c0c930dc8258952c868de5dc81b54765c1a0.
• Manifest: sha256:b34a4dcd71cd536a7f5a3a51d76d53ae5af3d0ce0f18783e71c7f01da865b867.
• Sanitized runtime evidence: https://github.com/777genius/universal-agent-plugins/blob/a022a505df4e9b6627d911d935c5fff511451ecd/tests/e2e/results/chrome-devtools-live-clients-2026-08-31.json

The earlier exact-head lifecycle evidence, including real Claude CLI plugin discovery, remains available at https://github.com/777genius/universal-agent-plugins/blob/main/tests/e2e/results/agentplugins-chrome-devtools-multiclient-2026-08-30.json. It applies to the previously recorded head, not a new runtime claim for this revision.

No real user project or browser profile was used. The community directory short alias is being expanded separately; the README keeps the direct repository command until that publication is available.

[OrKoN]

@natorion do you know about https://agent-plugins.org/? should we add this plugin configuration?

[natorion]

@natorion do you know about https://agent-plugins.org/? should we add this plugin configuration?

I think we should!

[777genius]

Correction: the Windows timing failure is unrelated to the Agent Plugins package. I removed the test stabilization from this PR in 59380dd so the change is scoped again to plugin.json, mcp.json, and release configuration. The standalone test fix is now #2635, with 20 consecutive focused repetitions passing.