Extend the sweep: module-level orphans and job-level duplication

The review missed send_image's second downloader because the mechanical
checks only see self.* state and read functions one at a time. Name the
two hand checks that close the gap: single-caller module helpers are
the same finding as an unread attribute, and duplication is found by
asking who else does a job - two implementations drift silently.

AGENTS.md

@@ -218,6 +218,16 @@ but just as well a one-shot helper method. Count assignments vs. other
 mentions per name, confirm each suspect against the test fixtures and the
 Hermes base class, and delete whatever nothing touches.
 
+Two blind spots this sweep leaves, cover them by hand. First, the grep sees
+only ``self.*`` state — module-level helpers go stale the same way, so check
+their call sites whenever one smells redundant (a single-caller wrapper is
+the same finding as an unread attribute). Second, duplication is found by
+naming jobs, not by diffing text: before judging any function, ask who else
+does its job (downloads? image materialisation?) — two implementations of
+one job are one too many, because they drift silently until behaviour
+differs (an uncapped downloader next to a capped one shipped here for
+months).
+
 ## Configuration surface
 
 **One field, three coordinated names — declared once on `ChattoConfiguration`.**