cli: mosaic talk prints only the reply to its own message (row 142, #1636)

Researcher's row 142 round 3 (agents/researcher/work/queue-142/r3/
row142.patch, packet dcc2b2936), applied unchanged on dcc2b2936.
Candidate manifest c847d8fe...dd81, 4 paths, rebased onto 277d1fa21
after row 146. Sage's landing gate passed, 24 steps. Researcher's 6
mutants fail by assertion on the new base. Filbert approved round 3 in
comment 28652.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/TOOLS.md

@@ -262,9 +262,11 @@ unit's `MOSAIC_CLAUDE_BIN`, from `--claude PATH` or else `command -v claude`
 PID namespace with a generated bundle, and `--pm` launches the business's
 `launch.by` instance at start. A host that starts ends the launches a
 crashed host left as `host-lost` and refuses with exit 3 on a
-`sessions.json` it can't read. `talk` sends a REQUEST and prints what
-arrives until the reply (polls every 2 s, `--wait` default 900; `0` only
-sends). `stop` sends SIGTERM to a run's runner after checking it in
+`sessions.json` it can't read. `talk` sends a REQUEST and prints only the
+reply to it, marking only that read (polls every 2 s, `--wait` default 900;
+`0` only sends); other messages stay unread for `mosaic inbox`, and
+`--follow` and `follow` print and read everything. `stop` sends SIGTERM to
+a run's runner after checking it in
 `sessions.json`. `launches off|on` revokes and restores `role.launch` for
 the business; running sessions keep running. `launches list` reads
 `sessions.json` and needs no broker. `talk`, `stop` and `launches off|on`