point CLAUDE.md at COMMS, so a new session finds it without being told

The channel is only useful if it is read, and relying on the owner to remember to say
"check COMMS" in an opening prompt puts the mechanism back where it started. CLAUDE.md is
loaded automatically, so the pointer belongs there: what the directory is for, that newest
date wins, and which streams exist.

Also states the split it is easy to get wrong — durable reasoning in docs/, coordination in
COMMS — and that a spent handoff should be deleted rather than left to be mistaken for
current.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CLAUDE.md

@@ -332,6 +332,24 @@ link-focusable). Half the app still does this; none of the new code should.
   re-exported from `src/workspaces/officerdev/src/index.ts` (named exports only — the barrel
   deliberately avoids `export *` for app modules to keep `appRegistryMetas` from colliding).
 
+## Before you start: check COMMS
+
+`COMMS/<work-stream>/` is a **tracked** channel between the agents working on this repo — several run on
+different machines, and findings used to reach each other by the owner relaying them from memory at the end of
+long sessions.
+
+**If your task touches a work stream with a directory there, read its files first.** They carry what is
+verified, what is merely assumed, what is known broken, and what is waiting on a decision. Newest date wins;
+each directory's `README.md` states the convention.
+
+Current channels:
+
+- `COMMS/sidecar-app-store/` — the app store, per-user Linux accounts, per-user Docker, and the per-user
+  Claude work that follows from them. Paired with `docs/per-user-linux-accounts.md`, which holds the durable
+  reasoning; the handoffs hold the coordination.
+
+Write there instead of asking the owner to pass something along, and delete a handoff once it is spent.
+
 ## Further Reading
 
 - `docs/navigation-audit.md` — **authoritative** on routing/navigation: the opaque-click anti-pattern,