feat(cli): meshbay-cli, a command-line client for members

Signs in to the hub, lists the account's groups and their folders, and
downloads and uploads files directly with each group's node, end-to-end
encrypted. With no argument it opens a two-pane interactive mode (Textual).
Session and device keys are kept encrypted under the system's key storage,
or a 0600 key file where there is none; node keys are pinned at first
contact; a new machine links as a device.

Packaged on its own on Linux (deb and rpm, on meshbay-common's venv, with a
man page generated from the parser) and frozen next to meshbay-node in the
full Windows installer, not the light one, with a self-test the build runs.
client/keys.py ports keyderive.js and is LGPL like it.

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

1 files changed, 24 insertions, 0 deletions

diff --git a/packages/meshbay-cli/src/meshbay_cli/errors.py b/packages/meshbay-cli/src/meshbay_cli/errors.py
new file mode 100644
index 0000000..319645e
--- /dev/null
+++ b/packages/meshbay-cli/src/meshbay_cli/errors.py
@@ -0,0 +1,24 @@
+"""
+Every way a run can end badly, as an exit code a script can act on.
+
+The library raises `CliError` with one of these codes; only `__main__` turns it
+into a message and an exit status.
+"""
+
+USAGE = 1
+AUTH = 2           # sign-in refused, no session and no passphrase, locked out
+NOT_FOUND = 3      # group, path, or a pattern that matches nothing
+PARTIAL = 4        # some items failed
+NODE = 5           # node unreachable, or it refused the connection
+NODE_KEY = 6       # a node's key changed since it was pinned
+VERSION = 7        # this client, or the protocol, is too old or too new
+REFUSED = 8        # refused before anything was sent: a name taken or not accepted,
+                   # a folder read-only or unavailable
+INTERRUPTED = 130
+
+
+class CliError(Exception):
+    def __init__(self, code: int, message: str):
+        super().__init__(message)
+        self.code = code
+        self.message = message