refactor: Add more checks to pre-commit

Updated existing pre-commit hooks and added some new hooks:

- Remove trailing whitespace
- Ensure every non-empty file ends with a new line
- Check YAML file validity
- Prevent adding large files
- Ensure any scripts with shebangs are executable

Added a GitHub action to run pre-commit on every commit. Removed any
existing actions which duplicate pre-commit.

Ran pre-commit on the codebase.

app/package.json

@@ -18,6 +18,6 @@
   },
   "homepage": "https://zmk.dev/",
   "devDependencies": {
-    "prettier": "^2.4.0"
+    "prettier": "^2.7.1"
   }
-}
+}