fix(cli): JSON error envelope shows command name + clearer rate-limit message

Two papercuts surfaced when prod's bootstrap returned 403:

  {"status": "error", "command": "", "error": "Bootstrap failed: {\"detail\":\"You do not have permission to perform this action.\"}", "data": null}

1. `"command": ""` — the JSON error envelope (printError under agent
   mode) reads from current_command state, but nothing ever called
   setCurrentCommand on the init subcommand. Hook into Node's
   preAction and Python's main_callback to stash the active
   subcommand name so error envelopes report which command failed.

2. Opaque rate-limit message. The backend's @ratelimit decorator
   raises PermissionDenied → DRF translates to generic 403
   "You do not have permission to perform this action." Users don't
   know it's a rate limit. Detect status_code==403 with /permission/i
   in the detail and surface the actual reason:
   "Daily Agent Mode signup limit reached for this network (5/day).
   Try again from a different IP or after midnight UTC."

Both fixes mirrored in Python (agent_mode_cmd.py, app.py) and Node
(agent-mode.ts, index.ts).

cli/python/src/mem0_cli/app.py

@@ -236,6 +236,13 @@ def main_callback(
         _fire_telemetry("version")
         cmd_version()
         raise typer.Exit()
+    if ctx.invoked_subcommand:
+        # Stash the active subcommand name so the JSON error envelope
+        # (print_error in agent mode) can report which command failed
+        # instead of an empty `"command": ""` field.
+        from mem0_cli.state import set_current_command
+
+        set_current_command(ctx.invoked_subcommand)
     if ctx.invoked_subcommand and ctx.invoked_subcommand != "init":
         # init fires its own telemetry from init_cmd.run_init with full M1-M6 props.
         _fire_telemetry(ctx.invoked_subcommand)

cli/python/src/mem0_cli/commands/agent_mode_cmd.py

@@ -61,10 +61,21 @@ def bootstrap_via_backend(
         print_error(err_console, "Agent Mode is temporarily disabled. Try again later.")
         raise typer.Exit(1)
     if resp.status_code != 200:
+        detail = resp.text
         try:
-            detail = resp.json().get("error", resp.text)
+            body = resp.json()
+            detail = body.get("error") or body.get("detail") or resp.text
         except Exception:
-            detail = resp.text
+            pass
+        # Backend's @ratelimit decorator raises PermissionDenied, which DRF
+        # translates to a generic 403 "You do not have permission to perform
+        # this action." That's opaque — surface as the rate-limit it actually is.
+        if resp.status_code == 403 and "permission" in str(detail).lower():
+            print_error(
+                err_console,
+                "Daily Agent Mode signup limit reached for this network (5/day). Try again from a different IP or after midnight UTC.",
+            )
+            raise typer.Exit(1)
         print_error(err_console, f"Bootstrap failed: {detail}")
         raise typer.Exit(1)