* fix(app): reuse project icon cache in new workspace
New Workspace omitted each host placement's effective icon revision, so its icon queries could not share the sidebar's memory or persistent cache entries. Carry that revision through the target projection.
* refactor(app): centralize project icon targets
Project icon consumers constructed equivalent cache targets independently. One target factory now carries each host placement revision through the sidebar, New Workspace, Projects, and Project Settings.
* test(app): inline project icon fixture
