Cowork (Desktop local-agent-mode) doesn't refresh an installed plugin after a marketplace version bump

Environment

• Claude Desktop 1.10628.0 (Electron 41.6.1), macOS (Darwin 25.4)
• Cowork / "Personal Plugins" installed from a GitHub plugin marketplace

Summary
A plugin installed in Cowork keeps serving a stale cached copy after the source marketplace is updated (new version + new skill). Updating/uninstalling the plugin via the Personal Plugins UI and fully quitting/reopening the app does not pick up the new version.

Repro

1. Add a GitHub plugin marketplace in Cowork; install its plugin (call it X, version 1.0.0, 3 skills).
2. Push changes to the marketplace repo: add a 4th skill and bump the plugin version to 1.0.3 (in both plugin.json and the marketplace plugins[].version).
3. In Cowork -> Personal Plugins, uninstall the plugin / re-add the marketplace, then Cmd-Q and reopen.

Expected: plugin shows 1.0.3 with 4 skills.
Actual: plugin still shows 1.0.0 with 3 skills.

Evidence (local state)

• The per-session snapshot under .../local-agent-mode-sessions/<session>/<workspace>/rpm/plugin_<id>/.claude-plugin/plugin.json still reads "version": "1.0.0" and the skills/ dir has only the original 3 skills.
• rpm/manifest.json shows this plugin's updatedAt is older than sibling plugins from other marketplaces that re-synced normally — i.e. this one didn't re-sync on reinstall.
• The remote marketplace is verifiably correct (plugin.json and marketplace.json both 1.0.3, 4 skill dirs present).

Workarounds tried (none worked): re-add marketplace; uninstall plugin from Personal Plugins; full Cmd-Q restart.

Impact: Plugin authors can't ship updates to Cowork users; the only apparent fix is manually deleting the cached rpm/plugin_<id> snapshot + manifest entry.