Switch single-commit boundary: append synthetic end (ts+1) instead of prepending start (ts-1)

Agent-Logs-Url: https://github.com/se-sic/codeface/sessions/5e09bdae-8463-4b3a-99f9-a79510a6ec5b

Co-authored-by: bockthom <5575176+bockthom@users.noreply.github.com>

Author: Copilot

codeface/util.py

@@ -541,12 +541,12 @@ def get_before_arg(num_months):
       del revs[0]
 
     # If the repository has only one unique commit (e.g. a brand-new repo),
-    # synthesize a start boundary one second before that commit so that two
+    # synthesize an end boundary one second after that commit so that two
     # distinct tags can be stored in the DB and an exclusive time-based
-    # analysis window [ts-1, ts] is created.
+    # analysis window [ts, ts+1] is created.
     if len(revs) == 1:
         ts = int(revs[0][1])
-        revs.insert(0, [str(ts - 1), str(ts - 1), revs[0][2]])
+        revs.append([str(ts + 1), str(ts + 1), revs[0][2]])
 
     # Extract hash values and dates into separate lists
     revs_hash = [rev[0] for rev in revs]