refactor: Replace pexpect with libtmux in BashSession (#4881)

Co-authored-by: openhands <openhands@all-hands.dev>
Co-authored-by: Engel Nyst <enyst@users.noreply.github.com>
Co-authored-by: Robert Brennan <accounts@rbren.io>

openhands/agenthub/dummy_agent/agent.py

@@ -18,6 +18,7 @@ from openhands.events.action import (
 from openhands.events.observation import (
     AgentStateChangedObservation,
     BrowserOutputObservation,
+    CmdOutputMetadata,
     CmdOutputObservation,
     FileReadObservation,
     FileWriteObservation,
@@ -54,11 +55,7 @@ class DummyAgent(Agent):
             },
             {
                 'action': CmdRunAction(command='echo "foo"'),
-                'observations': [
-                    CmdOutputObservation(
-                        'foo', command_id=-1, command='echo "foo"', exit_code=0
-                    )
-                ],
+                'observations': [CmdOutputObservation('foo', command='echo "foo"')],
             },
             {
                 'action': FileWriteAction(
@@ -81,9 +78,8 @@ class DummyAgent(Agent):
                 'observations': [
                     CmdOutputObservation(
                         'bash: hello.sh: No such file or directory',
-                        command_id=-1,
                         command='bash workspace/hello.sh',
-                        exit_code=127,
+                        metadata=CmdOutputMetadata(exit_code=127),
                     )
                 ],
             },
@@ -152,8 +148,6 @@ class DummyAgent(Agent):
                         obs.pop('timestamp', None)
                         obs.pop('cause', None)
                         obs.pop('source', None)
-                        if 'extras' in obs:
-                            obs['extras'].pop('command_id', None)
 
                     if hist_obs != expected_obs:
                         print(