🔧 Point repo metadata at Gitea; drop redundant .npmignore

The repository.url shipped github.com/tmueller/... but the real remote
is gitea.e1nsnull.de/tmu/..., so the npm page's Repository link 404'd.
Add homepage + bugs, fix the URL, and rename the CONTRIBUTING "GitHub"
reference to the forge. Delete .npmignore: when a package.json `files`
allowlist is present npm never consults .npmignore, so it was dead
weight that would only drift. Add "gitea" to the cspell dictionary.

package.json

@@ -10,10 +10,14 @@
         "pattern-matching",
         "typescript"
     ],
+    "homepage": "https://gitea.e1nsnull.de/tmu/tiny-pattern-ts#readme",
+    "bugs": {
+        "url": "https://gitea.e1nsnull.de/tmu/tiny-pattern-ts/issues"
+    },
     "license": "MIT",
     "repository": {
         "type": "git",
-        "url": "git+https://github.com/tmueller/tiny-pattern-ts.git"
+        "url": "git+https://gitea.e1nsnull.de/tmu/tiny-pattern-ts.git"
     },
     "files": [
         "dist",