feedkit: split the former maximumdirect.net/weatherd project in two.

feedkit now contains a reusable core, while weatherfeeder is a concrete implementation that includes weather-specific functions.

pipeline/dedupe.go

@@ -0,0 +1,5 @@
+package pipeline
+
+// Placeholder for dedupe processor:
+// - key by Event.ID or computed key
+// - in-memory store first; later optional Postgres-backed