Update documentation for SPC outlook support

docs/operations.md

@@ -64,16 +64,20 @@ and before each interval tick. If no jitter is configured in code, feedkit uses
 Poll failures are logged and do not stop the daemon. A failed poll emits no
 events for that source until a subsequent poll succeeds.
 
-## Conditional HTTP Fetches
+## Unchanged Upstream Content
 
-All current sources use feedkit's HTTP polling helper. By default,
-`params.conditional` is `true`, so the helper keeps ETag and Last-Modified
-validators in memory for each source instance.
+Most sources use feedkit's single-document HTTP polling helper. By default,
+`params.conditional` is `true` for those sources, so the helper keeps ETag and
+Last-Modified validators in memory for each source instance.
 
 If the upstream returns `304 Not Modified`, the source emits no events for that
 poll. Validator state is in memory only; restarting the process starts with no
 cached validators.
 
+The SPC convective outlook source polls multiple required documents as one
+bundle. It emits no event when a later complete bundle has the same fetched
+document bodies as the previous successful poll.
+
 ## Processing And Dedupe
 
 Every event passes through normalization first and dedupe second.
@@ -128,6 +132,7 @@ table in that same transaction. See the
 
 - scheduler goroutines and timers;
 - HTTP conditional request validators;
+- source-local unchanged-content state;
 - event channel buffers;
 - per-sink fanout queues;
 - the dedupe ID set.