README in French

README.fr.md is a full French translation of README.md (same sections,
code blocks and commands unchanged, same image and links). Each README
starts with a link to the other language.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

README.md

@@ -1,3 +1,5 @@
+English | [Français](README.fr.md)
+
 # Logstream
 
 A simple syslog sink: receives logs over UDP/TCP on port 514, stores them in