actually move all swarm-tui modules into a swarm-tui subfolder (#1840)

#1834 created a `swarm-tui` sublibrary for the remaining source modules that weren't in a sublibrary of their own, but I forgot to actually move them all into a `swarm-tui` folder.

swarm.cabal

@@ -592,6 +592,8 @@ library swarm-doc
 
 library swarm-tui
   import: stan-config, common, ghc2021-extensions
+  visibility: public
+  -- cabal-gild: discover src/swarm-tui
   exposed-modules:
     Swarm.TUI.Border
     Swarm.TUI.Controller
@@ -674,7 +676,7 @@ library swarm-tui
     swarm:swarm-scenario,
     swarm:swarm-util,
 
-  hs-source-dirs: src
+  hs-source-dirs: src/swarm-tui
   default-language: Haskell2010
   default-extensions:
     -- Avoid unexpected unevaluated thunk buildup