feat(cli): chat --follow

chat GROUP --follow prints the last messages, then each one the node pushes,
until Ctrl+C (exit 130). The connection is pinged every half minute; one
that closes, fails or stops answering is opened again, and what was said
meanwhile is read from the history. Each message is printed once, by its
(device, nonce) pair, which the node stores once. With --json, one object
per line. The man page lists it, with an example, and its FILES now names
the device keys kept for the Tier 2 check.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/packages/meshbay-cli/src/meshbay_cli/client/chat.py b/packages/meshbay-cli/src/meshbay_cli/client/chat.py
index 60629e2..22a99ef 100644
--- a/packages/meshbay-cli/src/meshbay_cli/client/chat.py
+++ b/packages/meshbay-cli/src/meshbay_cli/client/chat.py
@@ -48,6 +48,9 @@ class Message:
     text: str
     unreadable: str = ""   # why it could not be read: signature, epoch, ...
     trust: str = ""        # roster.RosterCheck's verdict on the signing device
+    # Which message this is, wherever it was read from — history or a push,
+    # which carries no id: the node stores a (device, nonce) pair only once.
+    key: str = ""
 
 
 class ChatKeys:
@@ -100,6 +103,7 @@ async def open_row(row: dict, keys: ChatKeys, group_id: str,
     if not (device and nonce and ct and sig):
         msg.unreadable = "envelope"
         return msg
+    msg.key = f"{b64(bytes(device))}:{b64(bytes(nonce))}"
     if not verify(group_id, epoch, bytes(device), bytes(nonce), bytes(ct), bytes(sig)):
         msg.unreadable = "signature"
         return msg