Slice 2 from #97 added a virtual "Modules" folder at the top of the
Workflows section listing every module-tagged workflow flat. In
practice it collides visually with any user-created directory also
named "Modules" (the tree shows two same-named folders containing
the same entries) and conflates module-ness with location. Modules
are a property (the `module` tag), not a place — saving a module
into a user folder shouldn't synthesize a parallel pinned location.
Discovery is already adequate via:
- The Tags section's `module` folder (existing — flat list).
- The green pi-plus-circle icon on module rows in their native
folders (existing per #82).
Slice 1 (auto-default Save-as-module on subgraph canvases) and slice 4
(subgraph definitions in serialize/insert) are unchanged and still
deliver the rest of #97's scope.