Support multiple repositories per execution

- Add RepoConfig type for per-repo path/remote/branch
- Options now holds [RepoConfig] instead of single repo
- YAML config file support (--config) for multi-repo setup
- --repo still works for quick single-repo usage
- Concurrent watchers via async (one thread per repo)
- --debounce flag overrides config file value

package.yaml

@@ -29,6 +29,7 @@ ghc-options:
 
 dependencies:
   - base >= 4.7 && < 5
+  - async
   - directory
   - filepath
   - fsnotify
@@ -37,6 +38,7 @@ dependencies:
   - text
   - time
   - unix
+  - yaml
 
 library:
   source-dirs: src