Transition from Mercurial to Git:

Repository has been converted to Git using fast-export
(https://github.com/frej/fast-export).

The following command has been used:
```sh
$ ../fast-export/hg-fast-export.sh -r ../hg-libervia-backend --hg-hash -M main
```

That means that previous HG hashes are annotated in the `hg` namespace.

`.hgignore` has been converted to `.gitignore`, and `_trial_temp/` has been removed as we
nowadays use `pytest` instead of `trial`.

While Mercurial is a great tool, more and more tools are only compatible with Git (e.g.,
ripgrep), and in particular `uv`, which becomes the new packaging de-facto standard in
Python. Also, many developers are more at ease with Git (even if Mercurial is actually
simpler to use).

.gitignore

@@ -1,6 +1,5 @@
-syntax: glob
+# Build directories
 bridge_constructor/generated
-.build
 build
 ctags_links/
 dist/
@@ -9,22 +8,36 @@ env/
 libervia_backend.egg-info/
 MANIFEST
 .mypy_cache/
+
+# Python artifacts
 *.orig
 *.pyc
 *.pyo
 .pytest_cache
 *.pyv
+
+# Editor files
 Session.vim
-stubs/
 *.swo
 *.swp
+.vim
+
+# IDE
+.vscode
+
+# Type stubs
+stubs/
+
+# Generated files
 tags
+
+# Test reports
 tests/e2e/report*
-_trial_temp/
+
+# Twisted logs and state
 twistd.log
 twistd.pid
 twisted/plugins/dropin.cache
+
+# Backup files
 *.un~
-.vim
-.vscode
-.gitignore