README: document accepted intake caveats

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01YECpkAwQUwgu7NVy91R8fW

README.md

@@ -89,6 +89,17 @@ Intake state (`intake_checkpoint` epoch-ms + post↔ledger↔task map) lives in
 the same atomically-written state.json. First intake run only sets the
 checkpoint to the newest existing post — history is never ingested.
 
+### Intake caveats (accepted, reviewer-flagged)
+
+- Status/ack comments are best-effort: a crash between a state save and its
+  comment can drop or (once) repeat a comment. Ledger and kanban stay
+  consistent — `shre-items done` on a closed item is a logged no-op and
+  `--idempotency-key pulse-<post id>` adopts the existing task on retry.
+- Bridge-output filtering is content-based (user name, `🤖` prefix,
+  `ledger:` tag line, threaded); renaming the poster or ignore list while
+  old posts are inside the intake window could ingest bridge output. The
+  comms API has no structured message metadata to mark authorship.
+
 ## v0/v1 limitations
 
 - **No real user-mention primitive.** mib007 comms has *agent* @mentions