Document why we override enum34 dependency

Added detailed comments explaining the enum34 override:
- RealtimeSTT uses pvporcupine 1.9.5 (last open-source version)
- pvporcupine 1.9.5 depends on enum34
- enum34 is incompatible with PyInstaller
- We don't use wake word features, so enum34 is unnecessary
- enum is in stdlib since Python 3.4

This provides context for future maintainers about why the override exists.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

pyproject.toml

@@ -73,7 +73,13 @@ torchaudio = { index = "pytorch-cu121" }
 
 # Override enum34 dependency to only install on Python < 3.4
 # (which effectively never happens since we require Python >= 3.9)
-# enum34 is an obsolete backport incompatible with PyInstaller
+#
+# Background: RealtimeSTT depends on pvporcupine==1.9.5 (the last fully open-source
+# version before 2.0+ required an access key). pvporcupine 1.9.5 depends on enum34,
+# which is an obsolete Python 2.7/3.3 backport that's incompatible with PyInstaller.
+#
+# Since enum is part of Python stdlib since 3.4, and we don't use wake word features
+# from pvporcupine (it's just an indirect dependency), we can safely skip enum34.
 [tool.uv]
 override-dependencies = [
     "enum34; python_version < '3.4'"