Add the Manage plugins tab (ui-settings-plugin-manager): package cards
with enable/disable switches, retry and uninstall, an install dialog
streaming pnpm output, and the selected preset's composition with per-row
switches and removal; the read-only list gains provenance facts.
Settings cards edit one scope at a time: ui-settings keeps one describe
mirror per settings scope (SettingsMirrorRegistry) and binds
{ namespace, scope }; ui-settings-plugins stages forms per scope, marks
inherited fields, and adds the skill-filesystem roots card.
Fixes surfaced by driving the browser end to end: the client gateway now
lets a call omit trailing parameters that accept undefined (PR3's
optional scope arguments failed the strict arity check), the plugins
install verb is `add` because the client namespace service reserves
`install`/`remove` (guarded by remote-method-names.host.spec), a plugin
module offers its main export as an addable `.`, and describing a settings
scope no owner registered resolves over the global instance's base and
never throws.
The web e2e scaffold can mount a profile runtime over fixture packages;
plugin-manager.e2e drives the tab and writes one field under a preset
scope; plugin-config and settings-chrome goldens are refreshed.
Yichen Jiang
1570eeeaee