Extends ctx.os.notify (the curated plugin OS door from #78685) with icon,
action buttons, and a serializable `activate` target. Body/action clicks
focus the window and navigate to the plugin's screen; activation paths
share one resolver (hermes-open-target.ts) with hermes:// OS deep links,
so `hermes://index-network/intent/1`, `/index-network/intent/1`, and
{ path, params } all land on the same hash-router route. Approval
notifications keep their existing session-scoped channel.
Salvaged from PR #84192 by @serefyarar (net diff of the PR branch applied
onto current main; branch carried merge commits so a single authored
commit preserves attribution).