Add agent plugin marketplaces and catalog sync

[Aaronontheweb]

Product contract

A marketplace is a metadata catalog. Marketplace add and update do not install a plugin or grant runtime authority.

Keep direct public GitHub plugin install from #2134. Keep private skill-server feeds. Keep netclaw skill sync as one complete external-source pass.

CLI surface

• netclaw plugin marketplace add <owner/repository> [--id <id>]
• netclaw plugin marketplace list [--json]
• netclaw plugin marketplace update <id>|--all
• netclaw plugin marketplace remove <id>
• netclaw plugin search <query> [--marketplace <id>]
• netclaw plugin show <name>@<marketplace>
• netclaw plugin install <name>@<marketplace>
• netclaw plugin update <source-id> updates only the named installed package.
• netclaw skill sync refreshes skill-server feeds, installed Git plugins, and registered catalogs.

Boundaries

The daemon owns catalog validation, durable snapshots, package source resolution, and source identity. A catalog entry supplies metadata and a candidate location. It does not bypass Git acquisition, path checks, the content scanner, or the skill registry.

A failed catalog refresh keeps the last valid snapshot. The sync result reports that failure. Feed and installed-plugin sync continue. A marketplace removal does not remove installed plugins without an explicit operator action.

The Agent Plugins 1.0.0 specification defines package format. It does not define a marketplace catalog format. The planning change must select and document the initial catalog format. The first release supports public GitHub sources only.

Acceptance

• Marketplace add and refresh install no plugin.
• Catalog search and show use one validated durable snapshot.
• A catalog install creates a managed plugin source with marketplace provenance.
• A named plugin update touches no other plugin or feed source.
• netclaw skill sync reports separate feed, installed-plugin, and catalog rows.
• Invalid entries and unsafe locations fail before persistence or acquisition.
• A catalog failure retains the last valid catalog and does not hide the failure.
• Tests prove the positive and negative boundaries.

Update PRD-004 and SPEC-004. Create an OpenSpec change through the repository workflow before implementation. Reuse the existing sync actor and registry.

Direct Git plugin work: #2134 and PRs #2160, #2161, #2162, #2157, #2158. Website documentation: netclaw-dev/netclaw-website#121.

[Aaronontheweb]

Source scope applies to every plugin lifecycle action. Direct and catalog installs, enable, disable, and remove must not start a complete remote pass. The daemon can refresh the inventory after a scoped action. Only netclaw skill sync starts the complete feed, plugin, and catalog pass. The current CLI uses the complete pass after mutations; see PR #2158 and its open scope thread.

[Aaronontheweb]

Draft PR #2186 defines PRD-004 CLI-015 and SPEC-017. The first catalog input is a documented subset of Claude .claude-plugin/marketplace.json. Agent Plugins 1.0.0 remains the package contract. The OpenSpec change and implementation still remain.

[Aaronontheweb]

PR #2158 now scopes named plugin actions to one source. plugin update --all syncs plugins without a skill-server fetch. The daemon keeps that scope across a plugin-only soft restart. netclaw skill sync remains the complete feed and plugin pass. Draft PR #2186 now rests on this contract. Catalog OpenSpec work and implementation remain open.