Rename cabal file

[dragospe]

Without this, you will get

$ make repl
wasm32-wasi-cabal repl app -finteractive --repl-options='-fghci-browser -fghci-browser-port=8080'
HEAD is now at 2e8dd81 Reset `components` global state on hydration failure. (#1299)
HEAD is now at 202b134 Merge branch 'main' of github.com:haskell-miso/miso-ui
Configuration is affected by the following files:
- cabal.project
Resolving dependencies...
Build profile: -w ghc-9.12.2.20250924 -O1
In order, the following will be built (use -v for more details):
 - miso-ui-0.1.0.0 (lib) (requires build)
 - app-0.1.0.0 (interactive) (exe:app) (configuration changed)
Created semaphore called cabal_semaphore_k with 16 slots.
Error: [Cabal-7125]
Failed to unpack miso-ui-0.1.0.0 (which is required by exe:app from app-0.1.0.0). The exception was:
  Error: [Cabal-7036]
Package .cabal file not found in the tarball: /home/pdragos/Code/haskell-miso/miso-sampler/dist-newstyle/tmp/src-26246/miso-ui-0.1.0.0/miso-ui.cabal

(note that it's looking for miso-ui.cabal).